Maddening: Screen Freezeup!

I may have posted this on the SDMB before, but such thread is nowhere to be found.
Specifically, sometimes the screen will freeze when I’m on the Internet–usually via AOL. The only way I can unfreeze it is to shut the console off and restart it. It’s enough to make me want to throw something! :mad:
I have a Compaq 4000 and Windows 98 Plus! I concede it’s older hardware…but what is freezing it? I only have this happen on the Internet.