Just installed MW2 onto this comp with windows 7 and it won't load up the multiplayer, the single player and spec ops work fine.

-It beings to load up, gets the the black screen where the resolution changes then just stops loading there, have to ctrl+alt+del to get to task manager to end to end task.
-I did have it working on this computer before when i was on XP but now i've changed to 7 its just a no go.
-Updated all my drivers; graphics+sound
-Done all the windows updates
-re installed
-deleted the local files for multi-player and re downloaded with the same result (hanging on black screen)
-tried solutions on some websites but they have not helped

I did think it was a driver problem at first because it was getting stuck on changing the resolution although as it works on single player i don't think thats the problem.

Any ideas?

(downloading black ops from steam soon to see if i get the same results with that, i.e. single player fine but multiplayer not working)
(Might get fraps or something like that to show you what it does)

have you checked that your firewall/virus protection isnt blocking it?

and that you have the correct ports open on your router?

I turned my firewall and virus protection off the second time I installed it and started up multiplayer.

What are the correct ports I should have open?

Google it :D