Hi Jim.
I've replied to this before and nothing has changed.
Your display issues are most likely the graphics hardware in your old PC combined with the slow CPU can't do squat performance wise.
Windows XP is VERY GUI and memory intensive, one thing to try, is right click on the "my computer" icon and select advance-> perfromance->settings and under visual Effects select custom and turn every thing off.
Also make sure all unessary tasks are disabled.
Bottom line is you need a PC that was made this decade
, you can get dells for under 200 bucks from the outlet store, I got one two weeks ago for 184.00 buck, 2.4 ghz celeron complete.
Just keep checking