This is the story. I noticed that the CPU was running slightly hotter than normal at like 65 C (windows was running some networking program that continued to run despite me disabling it and caused increased cpu usage) so I decided to replace my current thermal pad with artic silver 5 thermal paste. After I replaced it, the computer ran well for about a week. I went on vacation for 3 weeks and the day that I came back i turned on the computer. It ran well for a few hours and then all of a sudden it just restarted.
After restarting, there was no video on the monitor and no POST beeps.
So I decided to figure out what was going on. First, I tested the monitor on another computer and it worked well.
I also took the the motherboard out of the case and put it on cardboard to test it out and no difference. I tested with only the video card, psu, cpu, cpu fan and 1 stick of RAM but still no post. I even removed the RAM and video card but still no post.
I tested the power supply with a voltmeter and all lines showed appropriate voltage.
I finally took the CPU off the motherboard and looked for broken pins. There was 1 bent/broken pin on the motherboard and I sent the mobo back for RMA.
After receiving the new mobo and hooking the system back up to test it, still no solution. When the computer starts, the cpu fan spins, all lights go on (I don't feel the heatsink getting that warm though and the cpu fan spins at a slower than normal speed I believe).
I have no idea what is causing the problem. It can't be the mobo, I have tested with each stick of ram separately, tested the psu voltages, tested the monitor, but still no clue.
Could the CPU really have gotten messed up? I looked on the bottom and I didn't see anything abnormal and I read that an i5 cpu will rarely go bad. The temperatures weren't that high (maybe at most it would reach 70 but idling from 43-55 most of the time).
I don't have a spare CPU, video card, RAM, or mobo/cpu to test the sytem out and it would really be a pain to go out and buy these components to test and then return them later so if anyone has any idea on what else I can try before doing this, please let me know.
You have sort of answered your own question. You say you now have a new mobo and the fault still remains and that your psu voltages are all correct. So you have three possible reasons. Faulty cpu, faulty gpu or faulty memory. If the gpu is faulty then I am guessing the system would still boot - just with no video. So you would get all the familiar noises you would get when the system boots normally. Also you say the cpu isnt getting warm so that to be would again suggest it isnt a gpu fault. memory faults would usually anounce themselves with that lovely 3 beep code we all enjoy. So if i had to stick my neck out i would say everything points to your cpu. But as we all know nothing is for definite in the wonderful world of I.T!