When I put a cd in my cdrom to install programs, winxp professional say "error on windows installer, must be downloaded again" I do what?

Try doing this to find possible causes of your problem. Right clik My Computer and select "Manage". On the left, double clik "Event Viewer". Rite clik on "Application" and select "clear all events". Do the same thing with "Security" and "System". This will clear all the "Events". Restart your machine. Then, after it Does the problem, reboot, check the "Events" in the 3 places that you previously cleared. You should find some clues in there as to what happens when the machine locks up. If you right click on an event and go to properties, it gives you an explanation as to what happened. At least that's how I recall it works from my memory. Good luck. Let us know how you make out.