I've got a home theatre PC which I built myself and have been using for about 4.5 years now without issue - the only components that have ever needed replacing have been the case fans. Recently, I've been getting unexpected shutdowns - no warning at all, one moment it's running fine, the next it's off. This normally happens within a few minutes of powering up.
I've narrowed the cause down to the TV tuner card I use - a Hauppauge WinTV Nova-TD 500 plugged into one of the two PCI sockets. When I remove the card, the computer is fine, and happily sits there 24/7 with no issues.
The other PCI slot is occupied by a wireless network card. If I move this to the slot normally occupied by the TV card, everything is still fine. If I put the TV card into the slot normally occupied by the wireless card, the machine won't even power on.
If I put the TV card into another PC in the house - a 10 year old desktop PC with a Asus P4P800SE motherboard in it everything seems fine - drivers installed, will sit there for as long as I can be bothered to monitor it without issue.
As far as I can tell then, the problem is either down to the TV card itself or the motherboard in the HTPC (an MSI K9AGM3-FIH) But I have no idea how to narrow this down any further. Both components seem fine in isolation, but when used together they just don't work.
Can anyone suggest ways I can find out what's going on without just replacing both components?