M17x R4 Running Hot

I'm having a very recent problem with my mid-2012 M17x R4 running very hot. I've checked the vents and there is no dust that I can see. I clean them frequently. I haven't installed any new software or changed anything in the system but the computer is getting so hot I can't even touch it. I've had to shut it down several times to prevent it from overheating. It's getting to the point that I'm afraid to boot it up at all. I can't find a solution since I don't even know the cause of the problem. I went on Dell's support site and a diagnostic was performed. No problems were detected but I don't really trust the analysis seeing as I ran a Dell System Detect just prior to the diagnostic to check for new drivers and it said there was a driver update available for my AMD graphics card and I have an NVIDIA graphics card not an AMD. The System Detect is very unreliable. Dell installed the SupportAssist on my computer again during the diagnostic but it immediately started the causing the same problem I had with it when they switched out the AlienAutopsy for SupportAssist several months ago: the fans went crazy. I had to uninstall it again. I have no way of finding drivers or properly diagnosing this system to try to figure out why it is getting so hot. I want my computer back in working order. Any ideas on how I can proceed?