Black Ops problems

When I try to play a multiplayer game it goes to the end of the loading line and just stops it does to same with zombies as well but the campaign works I really dont know if its a disk issue or the xbox but i just want to play black ops can anybody help me

 

im playing so there ok

 

Then its definently a disk error do you know a way i can fix it

 

wipe it with a damp cloth or re rip a copy.

 

oh you could install to you hard drive 360.

 

I figured it out it works now i just had to install my friends game and it works now can so one lock it and move the post