Cold Boot Good, Warm Boot Bad

Greetings all.

The PC has been working fine for three+ years, and about a year on present PSU, but has started behaving badly.
Lately the PC boots up fine from cold, but when I do a warm reboot most of the time it doesn't reboot at all. The screen doesn't turn on, it doesn't check the memory... Sometimes it gets as far as the point where it should beep and go into the OS... but it just hangs there.
If I leave it for a while ( 5 - 10 minutes) and press the reset button it will usually boot fine.
If I try and power down the system after a warm reboot by pushing and holding the power button, it doesn't power the machine down but instead has the same effect as pressing the reset button.

Does this behaviour ring any bells with anyone?

I have had the PSU replaced, but it has not fixed the problem.

Cheers

Mark

Tyan Thunder K7 2 x Athlon MP2600+ 2.5GB ECC RAM Quadro 900XGL DVStorm2 Hercules Soundtheatre 4 x SCSI HDDs 2 X Pioneer DVD-R Adaptec 2904 SCSI card for DLT drive.

think i've had this before and it turned out to be a bios setting , cant remember what tho, have you tried reseting the bios to the default settings?

suppose it could also be a hardware problem most likely the memory , run memtest and see if that reveals anything http://www.memtest.org/#downiso

Your system sounds power-hungry with all those HDDs. Spinning those up will need a bit of oomph at boot-time. Can you / have you checked the Quadro in another machine as well?

It is most likely the PSU, this is the reason you changed it the last time? I say this because I've had similar experiences (but not my own machine). Although it was the other way round, cold boot no good, warm boot OK.

What PSU do you have?

Thanks for your suggestions.
Three of the SCSI hard drives have their spin-ups staggered, so they don't all spin up at once.
The PSU I am using now is a TAGAN 480W TG480-U01. I changed it to this from the NMB I had before purely on the basis of noise. The NMB (430W) is very noisy, the Tagan very quiet in comparison!

Just to rule out PSU supply, disconnect your non-boot drives and any other optical drives.

You could also try removing the Adaptec and the Creative cards and re-introducing them one at a time, see if the cards cause the lack of re-booting.

Also, if this proves problematic, just make sure the Creative drivers are installed fully. I've had systems be unstable, freeze or be extremely tempramental with such cards installed. Does it have a DOS component? (You don't say what OS you are using but I'd guess either XP or 2K so this may be irrelevent).

Also, just the fact that a Creative card shares a hardware PIRQ# can sometimes be a problem. Your BIOS should report on INT assignments. Try moving the Creative (or Adaptec if the add-in cards themselves conflict) card (although I have not had the exact card you have, it seemed to be a common issue amongst the brand range at one time). I've also had these cards crash otherwise perfectly running systems at random.

Sorry to be so pessimistic or critical of an add-in card, but I used to swear by Creative, then after a time of swearing AT them, I swore I'd never touch them again! (Tip: Use the supplied drivers or software from original CD as required, not downloads).

I'd try in this order;

Disconnect / Remove all suggested above TRY BOOTING / VERIFY OK
Uninstall Adaptec ASPI / Creative drivers TRY AGAIN / VERIFY OK
Re-install Creative card and drivers TRY AGAIN / VERIFY OK
Re-install Adaptec card and drivers TRY AGAIN / VERIFY OK
Re-introduce HDDs TRY AGAIN / VERIFY OK
Re-introduce optical drives TRY AGAIN / VERIFY OK

I'd guess this gives the best idea or being able to verify or narrow down the problem. If the problem remains with everything out and all drivers removed, try resetting your CMOS and setting only the options you understand / need. Leave everything else as default.