AIM compatability issues

Okay, so I've got a new Dell Studio XPS running Win 7 Premium 64bit. I use AIM alot on my other computer...so I downloaded AIM, and it's just not working well. At all. I thought it was my internet connection, but Trillian works just fine (although I dislike it...alot and want the old AIM back!)

So: it boots up, AIM opens, I can change my livestream/etc, add/delete buddies. But as soon as I go to IM someone? The screen freezes mid-send, goes white-ish, and gives me a 'not responding' at the top bar for 1-2 minutes. Then it will send.

I'm a writer and use AIM to plot/talk writer-chat with a couple of other friends, and we are fast typers; I want to be able to send IMs without a lag?

I've tried disabling all sounds, etc, running compatibility for Vista (there's no option for 7) and even have tried installing older crappier versions of AIM. Same issues. I've googled to my hearts content, and have found no results...

If anyone can help me, I would be forever grateful. I just want this to work :0