Hi another place to check is your dxdiag. If you type this in the start menu search box and hit enter the image below will appear... If you look where it says 'operating system' it should say 'build 6001'
Strange not to see a windows version shown on the System information image. I thought any installed version of windows came up on this page.
Can this information be hidden somewhere else?
I did not see Windows Update KB935509 mentioned.!!! (This software update is a prerequisite for Windows Vista Service Pack 1 (SP1). This update helps improve reliability when you install or remove Windows Vista SP1.) See the following link:
Have you tried installing SP1 using a 'standalone' copy? Thats what I used and most others in this forum. I'm not sure how your getting the updates as SP1 isn't officially released yet. If you could explain where your getting the copy from or what type it is I/we may be able to help you more...