Error 1719 usually occurs when windows installer service could not be accessed. So many people may come across this kind of problem. Actually, it is not difficult to solve. After reading this article, you will get several solutions to this question.

Solution one:

Start the Windows Installer service.

1. Click Start, type Services.msc and press {ENTER} . Double-click Windows Installer.
2. Set the Startup type of Windows Installer to Manual.
3. Click Start to start the service. Note down the error message if any.
4. Click OK.

Solution two:

Unregister and re-register the Windows Installer to do that follow the steps provided below. 

1. Click Start, click Run, type MSIEXEC /UNREGISTER, and then click OK. Even if you do this correctly, it may look like nothing occurs.
2. Click Start, click Run, type MSIEXEC /REGSERVER, and then click OK. Even if you  do this correctly, it may look like nothing occurs, or you may briefly see an hourglass.
3. After you run this command, the operation is complete. Try your Windows Installer-based application again.

Solution three:

Try performing SFC scan on the computer.

1. Click Start, click All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator. If you are prompted for  an administrator password or for a confirmation, type the password, or click  Allow.
2. Type the following command, and then press ENTER:  sfc /scannow  
    [The sfc /scannow command scans all protected system files and replaces incorrect versions with correct Microsoft versions.]
3. A message will appear stating that ‘The system scan will begin’. Be patient because the scan may take some time.
4. If any files require a replace SFC will replace them. You may be asked to insert your Win7 DVD for this process to continue.
5. If everything is okay you should, after the scan, see the following message “Windows resource protection did not find any integrity violations”.
6. After the scan has completed, close the command prompt window, restart the computer and check.

Solution Four:

If you are not professional with computer, please use this registry cleaner tool. It is very easy to operate.

1. Download and install registry cleaner by clicking it.
2. Start registry cleaner, and on the interface click Scan button.
3. After scanning, click Repair All button.
4. Then your problem will be solved.

System crash often happens when we try to download something, when system is attacked by virus or when some system files are destroyed. And even sometimes we really don’t know what caused this problem. But we are eager to resolve it.

Actually, solving this problem is not difficult at all. There are two solutions.

First: Restore your windows to a time prior to the trouble.

NOTE: Before restore, please backup all important data on drive c:

For Windows 7 Users

1. Click Start , type system restore in the Search programs and files box.
2. Right-click System Restore, click Run as administrator.
3. In the System Restore dialog box, click Next.
4. Select a restore point in the list that’s dated before you started experiancing the issue and then click Next.
5. On the Confirm your restore point window, click Finish.

For Windows Vista Users

1. Click Start, type system restore in the Start Search box.
2. Right-click System Restore, click Run as administrator, and then click Continue.
3. In the System Restore dialog box, click to select the Recommended restore check box, click Next, and then click Finish.

For Windows XP Users

1. Click the Windows “Start” menu button, point to “All Programs” or “Programs,” and point to “Accessories.” Point to “System Tools” and click “System Restore” to launch the System Restore utility.
2. Click the “Restore my computer to an earlier time” radio button on the “Welcome to System Restore” page and click “Next.” This launches the “Select a Restore Point” page.
3. Click the most recent restore point in the “On this list, click a restore  point” list and click “Next.” Click “Next” again on the “Confirm Restore Point Selection” page. Windows shuts down, and System Restore automatically reverts your computer to the date you selected. When the process completes, Windows restarts automatically.

Second: Use a registry cleaner tool to fix this problem.

Many people recommend this software when they come across computer problems. It is easy to operate and time-saving.

Download and install registry cleaner by clicking it.

After installation, start registry cleaner and on the interface click Scan button.

After scanning , click Repair All button.

Sometimes when we search the internet, we may come across several problems that prevent us from using internet normally. 
                         

1. Responding very slowly.                                                                                                
2. Some pictures cannot be viewed and there is a little red cross on the corner.
3. Videos cannot be displayed.

To solve these problems is not difficult if you read the following methods carefully.

Method 1:  Clear cached data in Internet Explorer

Internet Explorer 7:

1. Open Internet Explorer 7.
2. Click “Tools”, and then click “Delete Browsing History”.
3. In “Delete Browsing History”, click “Delete All”.
4. Click to select the “Also delete files and settings stored by add-ons check box”, and then click “OK”.

Internet Explorer 8:

1. Open Internet Explorer 8.
2. Click “Safety”, and then click “Delete Browsing History”.
3.  In ”Delete Browsing History area”, click “Delete”.

Method 2: Reset Internet Explorer Security Settings.

1. Open Internet Explorer.
2. Click “Tools”, and then click “Internet Options”.
3. Click the “Security” tab.
4. Click “Reset all zones to default level”, and then click “OK”.

Method 3: Run Internet Explorer with No Add-Ons

1. Click “Start”, and then type “Internet Explorer” in the “Start Search” box.
2. Click “Internet Explorer (No Add-Ons)”. Internet Explorer opens without add-ons, toolbars, or plug-ins.
3. Test Internet Explorer to verify that it works correctly.

Method 4: Try a  registry cleaner  tool to fix the problem.

If the above methods fail to solve the problem. Please use a registry cleaner tool to optimize Internet Explorer automatically. It just needs a few steps.

1. Download and install registry cleaner by clicking it.
2. After installation, start it and on the interface click Scan button.
3. After Scanning, please click Repair All button.

1. Utilizing the Windows Restore configuration.
2. Downloading and installing the service pack for .NET Framework onto your computer.
3. Editing the Windows registry with the Microsoft Registry Editor program.

1. Click Start button, then click All Programs.
2. Click Accessories and then click System Tools.
3. Choose the “System Restore” option. The “System Restore” dialog will appear.
4. Select the “Restore my computer to an earlier time” option and click the “Next” button.
5. Select a checkpoint before the error appeared and click the “Guided Help (Registry Backup)” option. 
6. Click the “Next” button. Click the “OK” button and click “Next.” The computer will undergo the restoration process and restart.
7. After the Windows system boots up, click the “OK” button in the “System Restore confirmation” window.

Answer two:

1. Download the Microsoft .NET Framework 1.1 Service Pack 1 from below:
2. http://download.microsoft.com/download/8/b/4/8b4addd8-e957-4dea-bdb8-c4e00af5b94b/NDP1.1sp1-KB867460-X86.exe
3. Click the “Save” button in the prompt and select a destination location for the file. Find the file and double-click the file to run it.
4. Clcik desktop Start button, and then click Run. Type ”Regedit” into the “Run” in the text field and click the “OK” button. Then you will see registry editor appear.
5. Go to the left-side pane and navigate to the following entry: “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ASP.NET.” 
6. Find “VerificationCompatibility” in the right-side pane, right-click it and select “Modify.” Alter the “Value Data” to “1” and click “OK.”

Answer three:

I have ever used a registry cleaner software. Many of my friends and collegues also use it. It is a very good tool to resolve Bad Request Error 400 and many other computer problems. You can follow below steps:

1. Download and install registry cleaner to your computer.
2. Start registry cleaner and on the interface click Scan button.
3. When the scan process is finished, click Repair All button.

Do you know what causes the “http 400 bad request” error?

Better know about the reason of this error, then it wil be easier to resolve it. Http 400 bad request error usually appears when you use a web browser. If the URL you are trying to visit has another set of “HTTPs”, this error message always occurs on your computer. 

Let’s see how to fix the  ”http 400 bad request” error!

Method 1:

1. Download and install .NET Framework 1.1 Service Pack 1 from below link:
2. http://download.microsoft.com/download/8/b/4/8b4addd8-e957-4dea-bdb8-c4e00af5b94b/NDP1.1sp1-KB867460-X86.exe
3. Click ”Start“, then click ”Run” and type in the command “regedit.”  Wait for the Registry Editor to load.
4. Go to “Edit“ then “Find.” Type “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ASP.NET” and press “Enter.”
5. Right-click on the file name “VerificationCompatibility” when it loads. Select “Modify.”
6. Type “1” for the “ValueData” and press “OK.” Close the windows and restart your PC.

Method 2:

If your problem still exists or you want to try an easier and faster way, please try this registry cleaner tool. Many of my friends use this tool to repair their computer problems. It will repair your error in just a few steps. I think it can help you a lot. Please follow below instruction:

1. Download and install this tool by clicking  registry cleaner.
2. After installation, please start the tool. And on the interface, click Scan button.
3. After scan, click Repair All button.
4. Then you will find the http 400 bad request error is missing.