I think this is a hardware (or firmware) issue but it's something I've never come across before so any ideas would be appreciated.
The machine in question had problems (disk corruption - which may be a clue) and so I've put a new hard disk in it and reinstalled an OS - XPpro - and then SP2. That's about all that's gone on it so far.
It boots up and shuts down with no problems except that if I ask it to do a restart, it first recognises the HDD (on IDE-0) but can't find (after a long time) any boot data and then on ctrl/alt/del, it can't detect the HDD.
Turn off the power and on again and there's no problem and no apparent corruption.
As I've initmated the HDD is on IDE (primary/master) with master selected on the jumper. It's a DiamondMax Plus9 80GB UDMA133 and the mobo probably runs at 100MHz (is that a problem?).
The machine runs a 2.5GHz P4 on a GA-8SIML mobo with AMIBIOS, 512MB DDR266 memory.
I've done simple things like changing the IDE cable to no effect so any idea would be appreciated.
My next step, unless anyone comes up with anything better, is to strip out the few components in it (graphics card / modem (CNR?)) and see if I can get it working properly. Maybe see if there's an update for the BIOS.
Although it has a graphics card I see there is a graphics connector on the mobo, although I can find nothing in the BIOS about enabling/disabling it.