Win7 Major Issues on Parallels 5.0

Just bought the upgrade to Parallels 5.0. Read the reviews about the speed in Parallels 5.0 and aero capability.
Well... i have major issues with the speed of the virtualization, setting up aero and windows activation! I have a bootcamp partition so i setup parallels 5.0 use the bootcamp partition instead of a new install.

I'm have Macbook Pro (late 2009) 2.26GHz with 2GB RAM, as for the virtualization, i gave it 768MB RAM. Using Parallels caused my whole system to slow down and the spinning wheel to pump up frequently. I tried to activate windows in Parallels but it was soo slow that i gave up and went back to the good old bootcamp!

Is it the configurations that messed up the speed? Or the Parallels Tools causing some issues?

Help!!