To be precise - it reboots when a broadband modem is connected via USB. It doesn't reboot if the same modem is connected via a NIC.
It used to reboot between 5 and 60 minutes at random. So I thought it must be an IRQ conflict. I looked at the device manager and found the NVidia Geforce2 was on the same interupt, and was running MS drivers. So I downloaded the latest NVidia drivers and installed them. Now it reboots as soon as it goes into Win XP if the modem is connected to the USB port, and runs like a dream if it isn't.
This I think proves its an IRQ problem. However as the graphics card is AGP I can't move it to another slot. I cannot disable it as theres no other video. I cannot disable the USB ports because they are needed. And when I go into the bios to try and manually assign the graphics card and AGP to different IRQ's, I find they are all bundled together and I can only change both USB and the video to another interupt, not separate each.
The machine is a clients - an ADVENT desktop, and the original drivers aren't with it. However I have downloaded the mobo ones from MSI's site, and apart from the graphics card all others are MS and showing no conflicts.
Any help would be appreciated.