pc dont see my psp anymore

Hi, my pc (win xp pro SP2) does not see anymore my sony psp.
Since last saturday windows started to say that it was an unknow device or that i need to plug it to an USB 2.0 (thats the only ports I have), then now it does not even see it.
Only last night after removing all drivers for the usb ports I was able to see my psp but for less than a minute, then it said that it could not install my device properly and that was all, it could not see it anymore, I tried with 2 differentes cables already.
I never had problems before.
im sure it is a windows problem , not my psp.
Any ideas?
Thank you