Stuck at Install of 4.0

Hi there,
So I had 3.0 and Leopard. I updated to Snow Leopard and then needed to upgrade to 4.0. Downloaded and started the install process and it Detects an instance of XP that is suspended and requests that I shut it down. But, I cannot open anything in Parallels to shut anything down as it says that Parallels is not compatible with this version of OS X. So, I'm stuck. I can't shut anything down and can't install further. Help is appreciated!
W