When trying to load Word, a command prompt dialog box pops up for a few seconds before disappearing. Nothing else happens. The same problem occurs with most other utilities - it won't even run something simple like a ping command. The OS is Windows XP Home (no SP installed), and the Office version is Office XP for Students.

Any ideas as to what might be causing the problem? It's very frustrating.

Obviously a macro/trojan/worm/etc ..

Run the proper scanners and find out!

all very well, but my it's sister's computer and she doesn't have a virus scanner installed. to make it worse, windows installer wont run so can't install a scanner, and she wont have internet connection for about 6 months, so can't run an online scan. Any more ideas?

I'm not sure about McAfee, but Norton AntiVirus is a bootable CD. You can set the computer's CMOS setup up to boot from the CD. Then, pop the cd in the drive and restart the computer. It will perform a scan from DOS. Unfortunately, with no internet connection, newer viruses won't be scanned for.