Yes, where did you buy it?
Are you using it for the product it is intended for?
What error message exactly or code do you receive? That will help troubleshoot the issue further.
Ya, where it was bought is important to me. Granted that I didn't do an extensive search but I sure didn't find a source that I'd trust for buying Win 7 with SP1 already slipstreamed. In fact, while there may be others, the only legit place to get Win 7 slipstreamed with SP1 that I know of is Digital River. Even there it is not a for sale item just an open download where you must already have a valid product code.