Reboot during DVD operation

I built a computer with a soyo m/b, Pentium III 667 MHz, 128 MB 133 Mhz RAM, ATI Rage Fury Maxx AGP video card and a RDR DVD-ROM drive. The system rebooted a lot at first so I assumed the drivers should be updated and I did that and now the computer reboots randomly and less often but it seems that it only happens when using the DVD drive (not necissarily for DVDs) or immediately after operating the drive. What should I do?