check to see if this option is activated in windows xp pro , right click on the desktop choose propreties then screensaver after energy then in there search for the the options because in ther you will find an option that will probably solve the problem, i'm sorry i cant tell you the name of the option but here i don't have any computer wher i can see it:P
Solved...that did the trick. Thanks everyone for your input.
The option is Advanced Power Mgmt. I guess that my MB is an old POC so Windows didn't enable it like it's done for my other machines. The MB is an cheapo Azza.