My Ps3 is Acting Up! Help Plz!?

Okay, I have the Playstation 3 "Phat" and its a 80 GB, Okay since I have updated my firmware to 3.40, It will not read My Red Dead Redemption or Modern Warfare 2, but it will read Grand Theft Auto: Episodes from Liberty City and MAG. I have Fully Reformated my Hard Disk an the whole nine yards, and its still F***Ing Doing it! I need helpful advice, Can someone PLEASE HELP ME?

Suggestion:

Thats fscary it happened to me aswell. And it started ever since i updated to latest version my Red Dead Redemption doesnt work but some of my other games do!!!!!!
At one stage they continued to work but then they just started not working again.
Have u realised that the games that dont work are the ones u play most often. hhhhmmmmm
Very Interesting