power supplies and dvd

You fixed things without first learning what was wrong. That is the number one error taught in "Fixing Things 101". Never wildly speculate.

XP diagnostics only report what windows sees. Your computer hardware manufacturer (if he is responsible) provides comprehensive hardware diagnostics for that DVD that test DVD hardware - without complications created by Windows. Another fundamental concept of fixing things. First break the problem down into parts. You tried to test both hardware and Windows simultaneously - which only confuses you.

If Windows XP cause your problem, then why did you not also replace the glbutt in your home's windows. Clearly, using the logic that replaced the power supply, then you should have also replace windows glbutt since that too might have contributed to your problem.

Having made all those changes, now you must execute comprehensive hardware diagnostic on all peripherals to first confirm they work - long before even loading and addressing Windows XP problems.

Is your computer system manufacturer responsible? If not, then you must download hardware diagnostics from the peripheral component manufacturers. Once you have established that you have not complicated hardware, only then can you move on to fix Windows software problems. IOW break the problem down into parts, and then first solve test verify those parts.

Why, pray tell, did you even consider the PSU as a problem? That makes about as much sense as replacing windows glbutt to fix a Windows problem.

john