I'm guessing you're on a 32-bit computer, since you're running such an old operating system. Check and see if the version of IE you're running is for a 64-bit computer. More modern computers are 64-bit (the Win7 software has a 32-bit version and a 64-bit version).

You should open the Control Panel and choose to add or delete programs, and uninstall IE from there. Then make sure you have the correct program if you download and install it again.

SRS