My Xbox is Freezing but Its Not Red Ring of Death?

not long my xbox started to freeze on smack vs raw, i was so annoyed but ended up fixing it at the end i just wiped the diskclean and everything went back to normal. when i started playing gta iv it froze as soon as i went on, i looked at the disk and went damn all these laser burns luckily i went to lovely game and got a brand new replacement of gta iv, i went back on and played gta i froze like a mofo, i went to game and ask for new one because it wasn't working so they bought and gave me another new copy of gta iv. i went back home and played gta iv, it froze again iwas like bullsh*t. i played my other game like skate 3 that was fine for 30minute until it froze. then and played midnight club la that was fine until i did a race and started to freeze. oh yeah gta iv starts to freeze when i start a mission stuff like that, like i start it on ballad of gay tony and fine until the first 2 mission and startes freezing, then i go onto to pal lost and damned it freezes on the mission im up to and then on normal gta iv it freezes as well on missions. from all gta freezes the quickes. my friend who is a nerd he had rrod on his xbox he said it could be a rrod error something to do with the x-clamp overheating the gpu cos on the gta it does tend to get fuzzy. he got me a xbox 360 rrod repair kit online and got the next day he got all the repair kit done new x-clamp and he put on the thermal paste and stuff. i took it back to my place and played iv and it freezes
maybe i should just ring microsoft but couldnt be stuffed and to wait for them to repair it plus i dont think i even have warranty so yeah please help me out here maybe its a faulty hhd or dvd drive who knows
thanx

Suggestion:

If your friend has opened the console he has invalidated your warranty. The online 'fixes' for red lights are all bogus as you do not know which specific piece of hardware has failed inside without a microsoft diagnostic tool, which are not commercially available.