I had extremely slow response to my keyboard input on webpage forms and scrolling. I read in another post that it was caused by a Microsoft Windows 7 update on 2/27/2013. The fix that was suggested by Employee was to do Windows Restore. I did not have a restore point, so I just uninstalled that update. That worked for me and things are responsive again.
To uninstall update 2670838, follow these steps:
Click Start, click Control Panel, click Programs, and then click Programs and Features.
Click View installed updates.
Click Update for Microsoft Windows (KB 2670838), and then click Uninstall.
You will have to do a restart to complete the process.
I then went to the Windows Update and found that the update was again the que, so I right clicked on it and Hide it.
Hope this helps others.