Mayor Cubase 5 issues [Unsolved]

[L.F.]

Just bought Cubase 5 and the damn thing is crashing left and right. And ofcourse, only in projects which use the Virus Ti through VC.
Where do I start..
1. Sometimes after loading a project my VC simply says: Ti not plugged in, or there seems to be a problem with yout Ti... at which time I eaither restart the Ti (software on/off), and when that doesn't work I unplug/replug it. This sometimes helps, but at other times only way to get it working is restarting cubase and unpluging the Ti. And this happens very often.

2. When it works, and the project is open, after 20 mins or so my VC simply shows a blank VST (the Ti is loaded and working, but when opening the VST GUI it's blank; nothing there except a gray surface where the Ti GUI should be). This makes it impossible to edit anything and, again, I have to restart cubase and reopen the project.

3. When closing Cubase 5, 90% of the projects using the Ti VC cause cubase to crash on shutdown. This wouldn't be such a big deal but it often does this even when only closing the current project.

I've tried everything I could think of; updated the drivers, the .net and c++ redist, tried closing all background tasks while working, evenu pdated the bios and placed the Ti as a solo device on a motherboard usb hub (the only device on that particular hub, not a real usb hub ofc..)... nothing seems to help. I even tried all the 3.x betas of the Ti; 3.0 worked flawlessly for me untill the upgrade. Reverting to 2.75 is not an option as most new projects use the features of 3.0. But honesly I don't see this being the real issue IMO..
I have used the Ti on the same machine for 2 years running cubase SX3 and have had only minor glitches now and then. The main reason I upgraded to C5 was to make my setup more stable and more compatible with the Ti...

Please... any advice you may have is very much appreciated. I can't get any work done like this, and I've got quite a few projects which have to be finished soon


PC:
WinXP SP3 + all the latest patches
Asus Commando
C2D e6850 (@3.5 GHz)
2x 1GB DDR2 @ 800MHz
2x seagate SATA disks (Raid 0)
E-mu 1212m PCI
Fortron 450W PSU

P.S. The PC works fine and is stable, no glitches, no crashes in any other department.

Thanks in advance.