Motherboard or processor - which has failed

Horlock

Trying to identify the cause of a problem with my computer. Recent changes first (although feasibly not connected). Next Symptoms. Finally what I've done to test for errors.

Recent changes
Computer was working perfectly. I plugged in two old hard drives which had been disconnected a while back (in order to run tests on other sata hard disks) this was yesterday, I removed a lot of dust (duster, vacuum and compressed air) I also closed the case - it had been open for some months. Today I installed Cura (for 3D printing - although I didn't connect a 3D printer). I used the Cura software for testing a 3D model built in google sketchup.

Symptoms
The computer was running in the backround. Software running at the time: chrome (with a lot of tabs), firefox with only about 20 tabs, google sketchup, cura, possibly word. The computer was displaying to dual monitors.
I started working on a different PC, but plugged the second computer into the one of the dual monitors, and was using firefox on the first computer occasionally to help troubleshoot the second as the second computer was not online.
Suddenly the display on the monitor (which was not connected to the second pc) started vibrating. I thought this was odd, so switched the other monitor back to the first computer. This screen was not vibrating. I thought it best to reboot it. It shut down correctly, however, it would not reboot.

What I did to test.
Disconnected all non essential hard drives.
Allowed time to cool.
Tried again.
Windows began to start up then a series of beeps and restarts.
I booted into bios. Happy to sit in bios indefinitely, can view bios data (not very helpful).
So far I'm thinking neither motherboard nor processor.

So I took took the main hard drive out and swapped it to another computer. It works in the other computer.
So I took the graphics card out and swapped it with one from another computer. Exactly the same symptoms.
So I removed the 4 sticks of memory (1 at a time), until only one remained same symptoms (also swapped the single remaining stick of memory) same symptoms.
So I removed the power supply from the other computer and installed it with only the bear essentials same symptoms.

I'm therefore thinking it can't be the power supply, it can't be the graphics card, it can't be the hard drive, it can't be the memory. The only things left seem to be the motherboard and the processor - however, as I said above I am still able to get into the bios - so the computer isn't completely dead.

Any opinions. I'm contemplating trying to replace either the motherboard or the processor (I don't have any spare of these to try switching about - non of the computers I have at home are same chipset). I might be better buying a whole knew PC, but I've got quite a lot of working bits.

Terry98

Horlock wrote: »

I booted into bios. Happy to sit in bios indefinitely, can view bios data (not very helpful).

Does the bios show a hard drive and cd/dvd drive? If it does could you try a os repair or clean instal?

Jim431

Why have you excluded the power supply. You should try replacing it.

GunJack

Jim431 wrote: »

Why have you excluded the power supply. You should try replacing it.

do this first before rushing into buying new stuff

also check all connectors/leads, a loose one whilst swapping bits could work free enough....

Big_Graeme

Those beeps are error codes how many and short or long beeps, also what BIOS do you have?

Sounds like the PSU has overloaded but it could be the board dying, I'd try a new PSU first.

Horlock

Terry98 wrote: »

Does the bios show a hard drive and cd/dvd drive? If it does could you try a os repair or clean instal?

Yes it does, but given that the OS works fine when I swapped the hard drive into another computer I wouldn't think a fresh install would help.

Horlock

Jim431 wrote: »

Why have you excluded the power supply. You should try replacing it.

Only because I get the same symptoms with a different power supply (I didn't try the suspected first power supply in the other computer as it doesn't have enough outputs - but I tried the tested power supply in the failed computer).

Horlock

Big_Graeme wrote: »

Those beeps are error codes how many and short or long beeps, also what BIOS do you have?

Sounds like the PSU has overloaded but it could be the board dying, I'd try a new PSU first.

I think I may have given a false description of the bleeps. They don't sound intentional, ie not distinct bright sounding bleep, more a quick series of very dull sounding clicks, it is not possible to count how many, they are too fast.

I do have a third PSU here, which I could try, will need to check that the computer it is in works first - but it should do. Am i right in thinking that you are thinking if it isn't the PSU then it will be the motherboard not he the processor? I don't really know whether it is worth the price of a new motherboard. I never liked the old motherboard (it is a dell one manual here http://ftp.dell.com/Manuals/all-products/esuprt_desktop/esuprt_studio_xps_desktop/studio-xps-8100_Service%20Manual_en-us.pdf), but/and the processor has served me well. The processor is an old i7 860, and so it would mean buying OOD tech to get it working again, but the old i7 seems more than capable of handling everything i give it. I've not kept up with computer tech for a long time, and this computer has been great. Obviously its been upgraded over time, now has 240gb ssd and 10gb ram, but I have no idea how a cheap modern processor would compare with an old decent processor.

moneyuser

Have you tried the onboard vga? Used different video cables? Loose connection?

Fightsback

Faint hope but CMOS battery in the Mobo ? Does sound like a failing mobo.

Horlock

moneyuser wrote: »

Have you tried the onboard vga? Used different video cables? Loose connection?

Afraid it doesn't have onboard vga