I bought this psp 1000 from a buddy of mine and he told me that it wouldnt read UMDs cause it needed a software update. I updated to 6.20 and it updated at 90% and stopped and I had to end up taking the battery out and restarting it. After that it worked to same. As soon as I even close the UMD door no matter if the is a game in it or not it says DISC COULD NOT BE READ. Anybody no what might be wrong, and what I should to?