PC spins up for 15 seconds then reboots.

[sonicstar]

Hi all,

I'm putting together a PC from a friend's used parts. It's an intel system and all parts are compatible. Here's what I've tried so far:

- Removed all non-essential hardware, only the CPU, GPU [not essential, but this is not the issue], PSU & a single stick of RAM is installed (tried with multiple types/ flavours of ram).
- I am not getting any output via MOBO VGA or card DVI on the monitor.
- I've ran a test outside of the case and shorting is not the issue.
- I don't have a buzzer.
- Originally there was no CPU cooler on the build when we first tested, so we thought this was the issue. However, I've since added one and the issue persists.
- MOBO has been unused and in storage for a little while, but not too long.
- MSG light is constantly on (I wired the case's HDD light to the MSG headers).

Anybody have any ideas about what to try next/ likely issues?

[Edits]
1: For readability

 

[Compuser10165]

List full system specs.... Double check every cable from the PSU. Try only one stick of RAM (in the appropriate slot). Did you try to power it on with no CPU cooler? That will result in CPU overheating but shouldn't cause any problem on the long term if you added a CPU cooler afterwards. Maybe you MOBO requires a BIOS update to support the specific CPU. Again, full specs.

 

[sonicstar]

Edited: Duplicate Posts

 

[sonicstar]

List full system specs.... Double check every cable from the PSU. Try only one stick of RAM (in the appropriate slot). Did you try to power it on with no CPU cooler? That will result in CPU overheating but shouldn't cause any problem on the long term if you added a CPU cooler afterwards. Maybe you MOBO requires a BIOS update to support the specific CPU. Again, full specs.

I'll grab the spec list when I get back onto my PC. Just to add though, I've found an old LED and wired it up to the Buzzer header and

I'm getting continuous short beeps,

which is a power issue according to manual. I've double checked all cables from PSU. I've tried 1, 2, 4 and no sticks of ram of 3 different types so fairly certain it's not that. And yep, to confirm the cooler is on now.

Is the power issue indication a 100% guarantee that PSU is the issue, or could it be some sort of MOBO power management, if such a thing exists?