Belarc Advisor can be downloaded from here: http://www.belarc.com/free_download.html
Video (Press HD Top Right for Clarity)
If using this utility and have obtained a Windows Vista or Windows 7 product key note that for an OEM install (i.e. Windows preinstalled by Dell or another Vendor) it will only yield the OEM product key and not the Retail product key. The OEM product key is useless to you as it is generic and will not activate via the normal retail methods and you should instead take a note of the key on the COA.
If you are unsure whether or not your product key obtained is OEM or Retail then look at the following threads depending on your version of Windows:
- Windows Vista: http://forums.mydigitallife.info/threads/2581-Vista-OEM-SLP-keys
- Windows 7: http://forums.mydigitallife.info/threads/10370-Windows-7-OEM-SLP-Key-Collection
If your key matches one of the keys displayed here it is OEM.
Hint when going to the website, press [Crtl] and [f] and use the first 5 digits of it for a search, if you don't find the key it is unique and can be activated via retail methods, if you do find it is OEM.