hotrod4x5 - 12:40 am on Apr 21, 2010 (gmt 0) [edited by: bill at 4:12 am (utc) on Apr 21, 2010]
The problem came back, so I did more thinking and research. Also recalled what the Dell service tech did a year and a half ago. He replaced the mobo, but used my old processor. So the other day, I installed a temperture sensor program and my cpu was peaking at 180 F. It occurred to me that when he moved the cpu from one mobo to the other, he did nothing about the thermal paste.
I got some Arctic Silver 5, cleaned the processor and heat sink and put on the new paste. Now she runs like new! Maxes out at maybe 120 degrees when I do something really intensive.
Just thought it might be good to post an update for anyone with similar problems.
[edit reason] a little cleanup [/edit]
[edited by: bill at 4:12 am (utc) on Apr 21, 2010]