I decided to change the thermal paste on my desktop now its refusing to turn on, I have had this situation once before and it fixed itself, I can only assume I did not connect a power cable or something because I had to remove everything to remove the motherboard because the heatsink was screwed in from the right side. Is it possible to provide a picture and some of you could point out where I went wrong, I'm crushed this is what I use to work and it comes at the worst possible time too. warranty ran out years ago.
assuming you did not remove cpu from socket so bent socket pin is out of the question, you have a No POST issue if no video on screen. Make sure 24/4 pin power connectors are properly attached (double check, pull out and push in again), remove gpu riser cage from PCIe slot and connect monitor to on board iGPU video port, remove both ram, put only one ram back in DIMM 1 (test this step w each ram). Also reset CMOs jumper on motherboard. There are two small green jumpers next to DIMM. One is probably for clr CMOs the other for clr pwd. And make sure front panel 9 pin connector is properly connected to rainbow colored header on motherboard. Pic of motherboard.
I fixed it, power cable was not connected to the motherboard and usb was in the wrong place, now its saying cpu fan failure when I can see it working fine and its not overheating, what is that about.
Ill check it out, any recommended programs outside of Bios. I see 3 fans listed in SpeedFan, Fan is doing 800RPM, second 2000RPM and third between 2200 and 4200.
HWInfo also gives me simmilar numbers, could it be faulty reading or because I have 2ssd and 1 hdd installed. I'll remove the hdd and see.
Most likely you swapped the CPU fan with a different fan (top or front). The Dell BIOs is often programmed to recognize specific fans for specific headers, mix them up and it will tell you something is wrong.