I run windows XP. When loading some web sites, my computer freezes and I
have to do a hard shut down to turn it off and restart (contr-Alt-Del does
nothing). I've always used Internet Explorer. Then I got the idea to
download Mozilla Firefox. I stopped having the problem until one day, I
replied yes to download some sort of flash media something or another. From
that point I started having the problem again.

I don't recall exactly when it started doing it, because I went years
without having the problem.

Any suggestions?