Sounds very unusual this, and I'm not sure how you can go about investigating what's causing it.
My initial thoughts on this, are perhaps you need to update the ASPI layer for the CD-ROM stuff as perhaps PMM has installed something that's causing a driver conflict (thus causing your machine to reboot).
I think the first thing to do, would be to get it so that XP shows you the BSOD (Blue Screen of Death) that's occuring. To do this:
1. Click start, and then right click on 'My Computer' and choose 'Properties'
2. Click on the 'Advanced' tab, and then click on the 'Settings' button under 'Startup and Recovery'
3. Untick the option 'Automatically restart'
4. Click on 'OK' and then 'OK'
Fire up PMM, and then make a note of the error that gets displayed on the blue screen that occurs and drop it back in here.