Are you doing an in-place Upgrade of Vista?
These are complicated and can take many hours to complete.
Are you able to detect any progress? Is the processor light flickering at all?
If it fails it should roll back to Vista.
I hope you backed up all of your files and are prepared to do a superior clean install if it doesn't complete, or even roll back.
If you cannot afford to lose files you didn't back up, or for some reason can't do the preferred clean install, I would call MS tech support to help you salvage the upgrade. You paid for this with your copy of Windows 7.
When you are ready to clean install, let us know. You'll want to boot from the installer, stay connected to the internet to get latest drivers
/updates, select Custom and use Advanced drive tools to format.