You could download the install files for IE7 and save them to your desktop, uninstall the program, then use the installer you saved previously to reinstall.
or lets go back....back into time of the troglodytes....."I need a woman....I need a woman" ...
Opps!!!! wrong back ...not that far back
Do a restore point in XP "Back into time when all was well" The little windows were flying all around the screen. The sounds were of minute bells dancing in your head
then see if the problem is IE7 or your computer.....hard drive bad, memory bad, power supply bad, or just a bad software bug in a piece of software.....good lucks