What you describe sounds like an in-place Install gone bad. This is why most techxperts recommend you do a Clean Install, to avoid having all of the corruption from Vista imported into Windows 7.
Back up your files, gather your program installers as you will have to reinstall programs, boot Windows 7 DVD, select Custom install, use Advanced Drive tools to delete all partitions, create new one(s) as you wish, then format before installing Windows 7 to first partition.
If you have an Upgrade version of Windows 7, the DVD will scan the HD at bootup to see Vista and allow use of Upgrade version key, even if you go on to delete/create/reformat using the DVD's drive tools.
The installer is nearly driver
-complete, with newer drivers
arriving quickly in optional Windows Updates. Any missing drivers or favorite apps can be found on the Support Downloads webpage for your computer model, Adobe (flash, Reader) and Java (runtime, free Ofc Suite) websites.
If there was ever a time for a clean install, it is now with the best OS ever.