You can try MS Fix-it. If you don't have the disk and didn't download Win7 you should have the Recovery Console on your computer. You can try to do a repair from there.Please download and run MS Fix-it from here. These are instructions for Vista but they should work for Win7.Run the Recovery Console.
1. Eject and remove any discs or memory cards from your computer.
2. Click the "
Start" button on the desktop to open the Start menu, click the small arrow icon to the right of the lock icon and select "
Restart".
3. Hold the
"F8" key on your computer's keyboard as Windows Vista reboots.
4. Highlight and select "
Repair your computer" choose your keyboard type and click "
Next".
5. Choose your user name, type your password if prompted and click
"OK" to access the System Recovery Options menu.
