yoo guys new here..and i got a problem..

Ok..I was playing cod4..everything was ok..but like after the game is finished it goes back to the lobby..but instead of going back my screen went black lolz..couldnt put it off with the ps button so had to do it with the behind button thingy on the ps3....Then i restarted it and tried it again...now the map didnt load..lol wtf.....and again it crashed while u see the loading map thingy...so again had to put the ps3 off on the bad way...Then i restarted it bla bla..couldnt read disk..lol pwned...so later i tried it again...its like..i can play multiplayer..get in a server..map loads..i can play...but after it, my screen turns black lolz....so really have nooooooooo idea what the problem is lol...oh and GTA crashes when i click multiplayer on my mobile..so its not only cod4

thx for reading lol..hope someone knows how to solve this..
and srry for my bad english.