Dell T5400 Overheat Problem(?)

I have a Dell T5400 that was a refurb I picked up about a year and a half ago. It has a single dual core xeon processor and 16gb of ram and an Nvidia Quadra 4600. I’m an architect, so I do a decent amount of rendering and CAD work. Everything was great for the first few months. Then, one morning after a windows update, I lost the ability to use dual monitors. This went on and off for a few months.

Last summer, having given up on the second monitor, and after another windows update, I suddenly got the BSOD. I tried a number of times to get it back up but couldn’t. The 1234 lights indicated a thermal issue and major errors. I let it sit for a few hours and came back to it. I was able to get it up again and ran a restore. Everything was perfect and my second monitor was back! The next morning when I restarted, back to the same issue. I realized that windows updated had reinstalled all of its new info and was causing the same old problems. I restored again, and again, all was good…until I unintentionally updated Windows again.

So last week I start working and five minutes into the day the box shuts down. I had noticed that the fans didn’t seem to be running, so I took the side panel off. After letting it cool awhile and after much cussing and wasted time I was able to restore and work the rest of the day. I had a guy come in to take a look over the weekend. He went through everything – hardware and software – and couldn’t find an issue. BIOS and Windows updates are current. He cleaned everything up and installed new thermal compound. It ran great for the next 5-6 hours.

Monday morning, five minutes in and BSOD. Took the side panel off, restarted, and worked for the next 8 hours with no issues. When I remove the side, I get the “thermal solution” error, but everything runs fine, just REALLY loud. So…What the heck is going on and how do I fix it???