Problems with Win 98/ IE

This computer is not responding at all when I open IE, I have to right click and go to explore, from the icon on the desktop, and even then it takes about 1 min. to load. I have a cable connection and have ran everything from Norton Corp. AV to Spyware Blaster and though it has found lots of spyware it still remains slow. I have been having this problem with my moms computer for the past couple of months and am wondering if upgrading to XP would be the way to go. I think there is a major virus in this computer due to it not responding in just window to some apps. I cannot defrag in regular mode and have to go to safe mode for this as well as scan disk. Sorry for the long post just need to know if I should kick this computer out the window or try to salvage it!

Any help would be greatly appreciated .......................

Mark