windows failed to start.A recent hardware or software change might be the cause.____

Hi,

I would suggest you to boot the computer into Safe Mode and check if you can boot, here are the steps:

1. Restart your computer if it is powered on.
2. Tap the F8 key after your computer initially powers on.
3. Once you see the Advanced Boot Options menu you can stop tapping.
 4. Use the up/down arrow keys to highlight your selection.
5. Select Safe Mode and press Enter.
6. You should see drivers loading, and then please wait.
7. You should then be at the Welcome Screen.
8. Logon to your computer using an account with Administrator privileges.

 http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode

Once the system boots into Safe Mode, try restoring the system and check if it helps, here are the steps:
1. Click Start, type system restore in the Start Search box, and then click System Restore in the Programs list. If you are prompted for an administrator password or confirmation, type your password or click Continue. 2. In the System Restore dialog box, click Choose a different restore point, and then click Next.
3. In the list of restore points, click a restore point that was created before you began to experience the issue, and then click next.
4. Click Finish.

You may visit the following KB Article link for reference:
 http://support.microsoft.com/kb/936212

You can also try startup repair, here is the link:
 
http://windows.microsoft.com/en-us/windows7/What-are-the-system-recovery-options-in-Windows-7

Please respond back with the status of the issue and let us know if you have any issues.

Azam – Microsoft Support.