|So it worked fine at the shop and didn't restart when you inserted a cd? And you've tried more than one cdrom?|
Maybe it's a heat problem. Did the shop have the cover off the computer? If so, it'd be cooler inside the case with the cover off.
Or static electricity can restart a computer. Are these restarts associated with you touching the case and getting a static shock?
If you haven't already done so, replace the cdrom's data cable.
Real men don't use AntiVirus; they just reformat