Call your computer manufacturer and ask fot a new set of "Vista Recovery Discs". How did you lose your partition ? Did you break the partition ? The key on the bottom you'll need if you plan to upgrade "Vista" into Windows 7. The "Key" is also recorded in your "Registry" but it is encrypted and you'll need a special software program to get it out. (There are many free KEY RECOVERY PROGRAMS)
You could just do a factory re-install with your "Vista Recovery Discs" from the manufacturer. If you made any back-up discs, you could recover personal info..... You probably should think about an Acronis Disc Image after you get Vista back to the way you want. (The pre-installed stuff maybe a necessary evil if you don't have any back-up or personal Disc Images)
To upgrade from Vista to Windows 7 would be 65.00 US including disc. To buy Windows 7 Home Premium is I believe, 199.00 US- W/O disc. Keep your Vista for the upgrade.