problems with media composer 5

Hi guys. I'm a newbie to Avid, I just downloaded the trial version and I'm testing it for our studio, which up till now was using Edius.
For some reason I got off on the wrong foot, since right off the bat I'm experiencing two accute problems:
1) Whenever I try to rearrange my workspace, and more specifically when I try to change the size of the composer, it keeps dissapearing and the only way I can get it back is by changing the format of the project
2) For some reason I can't see the video running in the composer. I can scrub through it and see everything, but when I push play nothing's happening. The screen remains black.
My setup is as follows:
Intel quad 9400
8gb ram
geforce 9800 gt
windows 7 ultimate 64bit
Thanks in advance