I had had Win 7 up for over a month when I tried to install something using Vista Compatibility and got this errorsee thread http://social.technet.microsoft.com/Forums/en-US/w7itprohardware/thread/c8434d39-e9a4-4950-bfff-5eac49fa2389I was sure I could remember successfully doing something using Vista Compat days before, so I restored earlier and all went well.But I didn't know what caused me to start getting that.Now I do.I had installed Nvidia 181.22 WITHOUT using Vista compat - I had NEVER used Vista compat in all my installs over the past month with 7000!I didn't realize this was a problem - I restored back to the 9th, installed Nvidia again (WITHOUT compat)(I wasn't hep yet!), and backed up (Acronis TI).Then I started playing with Comodo. I installed it, it wouldn't engage, I googled, and found that it needed to be installed with Vista Compat.I tried instaling it with Vista Compat and BANG - x05 error. AHA! The light goes on brightly! My Nvidia install (WITHOUT Vista compat) caused it.Restore previous image, install Nvidia 181.22 WITH Vista Compat, backup with TI, try Comodo install with Vista compat, and of course it all worked beautifully.NOW, the question is WHY installing the Nvidia vid card driver WITHOUT Vista Compat (which all seemed to go perfectly), changed the system such that any attempt to use Vista Compat after that, ends in access failure (x05)?????I'm sure that will give someone a headache, but for us users, the fix is easy. Assuming you have been regularly imaging your system as you go along! Kris -------- Gigabyte GA-EP45-UD3P, E7200 2.53@3.8ghz, 2x1gb OCZ Reaper1150@1203, EVGA 9800GTX+ N873 , BFG GS-650, Vista Ult 32 SP1 / Win 7 7000