QUOTE(zgim @ Nov 30 2007, 06:35 AM)

Nope, just the dashboard (or fw?) update on the nba live 2008 game.. After that, i can't play anymore. I tried the originals and it didn't play also. Howevr, the dvd movies are working fine, i tried original and backup dvd movies.
Rule out the game changing your firmware - that's not going to happen. A dashboard update is also not going to cause this. From what you're describing, the 'key' on your DVD drive is different from that on the console itself. This is why games don't work whereas DVD movies will. I don't know why people insist on comparing original DVDs to backups - subject to media, ALL devices capable of playing DVD movies will play the backup copy without any modification to the hardware/firmware.
Are you 100% sure that you haven't messed with the drive recently? If you are, then remove the drive and re-read the key - make sure it's the same as it was when you originally flashed it. If it is, it may be as simple as dirty/worn laser. Give it a clean first to see if it helps.