Unable to run Mozilla & Internet Explorer on Host OS...

I had some of this problem when I installed Virtual Box. When I am running Parallels Workstation 6 and the Guest OS is an install of Linux Mint 12, I do the Ctrl + Alt to release the mouse for the Host CPU. I keep Mozilla, IE, and Chrome open in the background. Mozilla hangs on opening, IE does not open at all unless I go to InPrivate mode, and only Chrome works properly. I use Firefox more than IE and Chrome, so this can be a problem.

HP Notebook Pavillion dv7 series
AMD Phenom II Triple-Core 2.1 Ghz
8 GB memory
500 GB storage
Wireless abgn
Bluetooth, Ethernet
Windows 7 SP 1 Host OS

Any thoughts...