Internet Explorer stops working

[tfg]

In Vista,when working Internet Explorer, it's not long before a box appears saying "Internet Explorer has stopped working" then it restarts, however , if I leave it alone then it's fine. I have looked in Help and Support but can't find anything obvious so has anyone else had to deal with this problem
thanks

[tfg]

sorted, scanned for malware and found over 450 infected files, wasn't my pc by the way so who knows how it was being used, works fine now tho