Hi all.
Over the last few days my new PC has begun spontaneously rebooting - sometimes after a few minutes running, sometimes an hour or so.  There doesn't seem to be any rhyme or reason to it, it just flips out to a black screen, then restarts.

This new machine has been running reasonably well for the several weeks since I finished it, it's the just the last couple of days it's started this silliness. It's done it twice while I've been typing this, so I'm having to save the message every dozen words or so.

The PC has an AMD 1800+XP with 2x 256 DDR PC2100 ram on a Gigabyte 7VTXH+ mobo, 133FSB.  Power supply is 320W P4 rated. The mobo has the latest BIOS. GFX is a GeForce2 Pro 32Mb.

I'm running a 52x AcerCDRom and a Liteon 24102b writer. HDD's are a Seagate UDMA2 8Gb and a Maxtor UDMA6 40Gb. There's also an NEC 100Mb zip drive and FDD. 

The only thing I've added in the last week is a Promise UltraATA100 TX2 IDE controller card, which I first thought was the culprit.  However, I've now got the HDD's and CD's running from the onboard IDE's, with the zip disconnected, and still the problem persists.  The only thing I haven't done is to pull the Promise card out of it's PCI slot and uninstall it. That unit has the latest BIOS, too.

Immediately prior to a reboot, there's a little 'Fssst!' noise, very brief and only audible because I have the PC alongside me on the desktop with the side off the case.  I noticed the LED on the underside of the Maxtor would flicker along with the sound, so I pulled the Maxtor also, thinking it might have been that HDD, but it still does it with just the Seagate and the CD's connected.

(it's done it twice again in the last 5 minutes)

Other factors? - I'm using PC-Cillin.  Local power is stable. W98SE. IE 5, OE 5.5. Don't run ZoneAlarm or any other monitoring apps.

Suggestions will most appreciated.
Ian Porter
Computer Guys
Arrowtown
New Zealand
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