15" unibody MBP (semi)freezes?

hey guys, this is my first mac, i'm fairly new to macs and OSX, so excuse my inexperience if this is a known issue, however..

i've noticed that on occasion the OS seems to semi freeze up. i can still use active applications, but the dock is unresponsive and other features such as expose don't work. at first i thought it was msn for mac - being a 3rd party app - but forcing a quit on that was fruitless. as was forcing a quit on all applicaitons. i attempted a normal shutdown but the machine freezes and i have to force the shut down by holding the power button.

its happened a few times now, i bought it late december and its happened at least 5 times since. i tend to use it regularly, between 5-8 hours a day, and rarely shut down the machine, opting to instead put it into sleep mode.

has anyone experienced this? is there a work around/patch (MS talk, i know :$) around that'll fix it?

thanks

 

cheers for the replies gents.

i tried adium, didn't really like the feel of it. theres too much going on and i like simple! the only thing about msnformac i dont like is the lack of webcam intergration. that aside, its good enough.

how good are the guys at genius bar? i'm in the UK and when i bought the MBP i was served by an 18 year old who didn't have a clue. i'm no mac fanboy, this is my first machine, but i did my research and knew what i was buying. i dont think he had much of a clue what he was selling. i was told in no uncertain terms that the graphics performance of the 13" MB was on par with the 15" MBP! so you can forgive me for being a little sceptical here!