No boot - no beeps, no video o/p, nothing.

[bandsaw]

This won't help but I have EXACTLY the same issue as that in dhyta23's thread - which I didn't want to hijack. PC was working all fine and dandy last night... come to turn it on this afternoon and it does the sum total of sod all.

I unplugged the mains lead, as you do when clutching at straws and left it 10/15 mins. As soon as I put the lead back in and switched the PSU on, the 4870 did an admirable hoover impression and stayed that way. All fans come on (bar the CPU cooler fan) but that's it - no video output, no beeps, nothing. The power button has no effect.

Taking the 4870 out = same problem.
Replacing 4870 with X1950Pro = same problem.
Taking RAM out = same problem.
Replace PSU with lower power, older PSU = same problem.

Of six LEDs on the 4870, three are green which then go out and three others red ones all get lit - the ones for temp and power cables. Both PCI-E cables are properly connected and I don't believe for a minute that temp is an issue. On the X1950Pro, the LED near the PCI-E connector stays red. Red is obviously never a good sign but I can't see both the 4870 and 1950 being knackered.

Current PSU is a Zalman ZM600-HP 600W and was absolutely fine, the "replacement" test PSU was a GlobalWin 400W SuperSilent somethingorother - granted, it doesn't have the guts to power the full system but I wasn't trying that, all I had connected was the mobo (I was after beep codes). It does the same trick... as soon as mains power is applied, all the fans come on. Pressing the power button does nothing.

System is:
E6600 @ 2.4GHz
Gigabyte GA-P35-DS4 (latest non-beta BIOS)
2GB (2x1GB) Corsair XMS2 PC6400 CL4 @ 800MHz, CL4, 2.1v
Sapphire 4870 1GB
Hitachi 500GB SATA HDD
No optical drives or other HDDs connected right now.
Everything is at default settings, no overclocking of any kind going on.

So, what I'm thinking is that the mobo is thoroughly shafted. Any thoughts?
Any and all help, advice and suggestions would be appreciated before I stump up for a new mobo (which would be a P45 job).

[bandsaw]

I've now had the PSU out (the Zalman) and have checked all the outputs (not under load, mind) and all seem OK.

[funke_munke]

I had a problem similar to this when attempting to overclock my ram a few months back, everything was clearly powered but not booting at all. I had to find a series of keys to press to force it to boot to a cd and update the mobos bios, after that it worked fine. If the same sort of thing doesn't work for you, being a similar problem I'd be inclined to lean towards the new motherboard route.

[sadbuttrue]

Have you tried reseating the RAM or trying 1 stick at a time?

[007]

Did you reset the CMOS/Bios settings ?

I know it sounds stupid ...but try to start the system with screwdriver (short circuit) instead of connecting the pins to the case's power button .

If no, as in previous post, I would start from mobo's test

[bandsaw]

Cheers guys - took the thing out of the case and tried everything - clear CMOS, shorting the power switch jumper, etc. Still nothing. The very fact the fans (case fans, not cooler) spin up as soon as the PSU is switched on suggests the mobo is for the scrapyard (just ordered a new 'un so here's to hoping it is the mobo!!!).

[bandsaw]

Rightio then, a new mobo (even tried an old Pentium D 2.8) did sod all... PSU?

It does however mean I've got an upgrade to a P45!

[peterb]

PSU looking like the likely culprit.

[bandsaw]

Just in case anyone else has this same problem, a new PSU (Corsair HX 750W) seems to have fixed the problem. Granted the older, P35 motherboard could well have been iffy too but the new P45 board didn't want to play with the PSU either.