Steinbergusers.com: VST Freezes Computer

Using Cubase SE1 (want to upgrade but don't know which version to get). Anyway, all works well until I install the Virt Instrument Collection. Both the one that came with SE1 VAP (value added package?) and I also got Virt Guitarrist 2, Virt Bassist, and GrooveAgent 3 which I've downloaded the upgrade to. What happens is that I can use the VST's with no problem but when I go to close the project Cubase freezes and won't shut down. I have to do a Ctrl,Alt,Delete to get Cubase to shutdown. I'm using WinXP SP2 with a Dell Vostro 200,Core2Duo 2.3ghz, 3 gig ram, 160gb mirrored raid drives. Any idea why the freeze up occurs? I've tried turning off the onboard audio card in bios, then read this can cause problems so I reversed that. Uninstalled antivirus software, gone back to a complete fresh install of XP including re-formatting the harddrive and loading only bare essentials to doing that again and doing a default install with whatever Windows wants to install as defaults. No luck. Everytime I use a VST the program will work wonderfully, but, freezes when I go to close it down. Any help would be greatly appreciated.