Computer build gets to POST then restarts.

[frankieonpcin1080p]

I'm recently making a PC for a family member but I ran into a few problems, I've done tests on the system by removing ram and replacing them and removing the gpu to use integrated graphics. yet either way I get the same problem which is hearing the single beep indicating the PC's posting and I also see the post page, however I cannot use my PS/2 keyboard to enter bios and It works fine on another system. I just breadboarded the PC with 1 ram module and just the cpu and the computer posts, then reboots like normal. Any reason why this is happening? Any help would be great.
Many thanks,
Franklyn.
PC Specs:
Q8200 Intel Core Quad
2X2GB Komputerbay 800Mhz Ram
Seagate Pipeline 500gb
HD7750
Antec vp450p
G41S-ES2L

 

[MundoDragon]

Do you have any way to swap out the PSU to try and eliminate it as the issue?

 

[frankieonpcin1080p]

I'll try getting the one from the system I'm using currently and will get back to you soon

 

[frankieonpcin1080p]

Ok, The PSU is working fine. Does the same process with a working PSU.

 

[frankieonpcin1080p]

From what I see the problem falls down onto the Motherboard or CPU

 

[MundoDragon]

I'd try reseating the CPU to make sure it is firmly in place. Also, try using a PS/2 keyboard to get into the BIOS, if possible. If all else fails, try popping out the CMOS battery from the motherboard for about 10-15 minutes. Pop it back in and boot up to see if resetting the BIOS helps. (Not sure if it is a new board or not).

 

[frankieonpcin1080p]

I've resetted the CPUu a few times today, the PS/2 Keyboard I have doesnt work for some reason yet it's definitely working. The Motherboard is seller refurbished tested and working, gonna try resetting the CMOS

 

[MundoDragon]

Just curious, did you remember to clean off and reapply thermal paste to the CPU after reseating? Also, what kind of CPU cooler are you using? Stock or third party?

 

[frankieonpcin1080p]

Ok, took out the battery for 15 mins. Replaced it yet same old. I'm using stock, and I also reapplied the thermal paste.

 

[MundoDragon]

Did you clean off the old paste with 99% isopropyl alcohol and a lint free cloth (or coffee filter, in a pinch) to make sure there aren't any air pockets/bubbles which restrict heat dissipating from the CPU to the heatsink? Also, what method and how much thermal paste are you applying? Sorry if this sounds basic. Just want to try and help without overlooking something. It happens to us all.

 

[frankieonpcin1080p]

I see, I have no isopropyl but I've cleaned paste of quite easily with cotton buds until it looks brand new. Have no idea what could be doing it, need to find out soon as this is a christmas present that I may need to order parts for.

 

[MundoDragon]

Meh, cotton buds are a no-no. They will leave fine strands on the surface of the CPU, which will restrict heat dissipation, some of which may not even be visible to the eye. I would suggest getting some alcohol and coffee filters to clean the surface of the chip, then try reapplying thermal paste. Could be a long shot, but worth a try before you start RMAing stuff. Good luck.

 

[frankieonpcin1080p]

Either way, I've reapplied some new thermal paste but the problem still persist. It's not a overheating problem because the process is in a loop and the CPU produces no heat at all tbh. I turn on the computer and the fans all turn on, the speaker then makes the bios beep, the PC then displays the Processor type and the memory with OK followed after it. It then hangs there for 4 seconds before repeating again.

 

[MundoDragon]

I would try RMAing the motherboard, if possible (not sure since it is refurbished), then while waiting for that to come back, get some alcohol and coffee filters, darn it. Total is probably less than $2. A modern processor can heat up very fast, which could be causing the restarts. I'm just trying to help here and cotton buds are a definite no-no for cleaning a CPU. Again, good luck.

 

[frankieonpcin1080p]

I found a compatible CPU that was working and the same happens, currently RMAing the Mobo. Hopefully it's fixed