Try this, bring up task manager (ctrl+alt+delete), on the menu bar click on file then click on new task (run). In the box that opens manually type
http://www.kellys-korner-xp.com/xp_tweaks.htm . Click ok and it should bring up the site. Scroll down to number 195 and in right hand column double click and in the box select run. Check with taskmanager the CPU usage. Once activity is low and stable then in task manager menu bar select shutdown and in dropdown menu select restart. Hopefully you'll get your desktop back.
We'll need to get rid of mallware next if successful. Try Ferret's links first.