CD-ROM causes reboot

When I insert a CD and try to open it, my system restarts. I have only had the system about one month and it has worked fine until now. I haven’t installed anything new since the last time it worked. I am running Windows XP SP1 with all the recent post SP1 patches. The motherboard is an ECS K7S5A with a SiS735 chipset. The video adapter is an ATI Radeon 9000 Pro. I have 512MB RAM and have run a diagnostic on it and verified that it is ok. I don’t currently have internet access for this PC so everything I install has to come from CD which obviously is causing problems trying to update drivers etc. Has anyone seen or experienced this kind of problem?