If you have the hidden restore partition then doing a restore will give you an OS like the way you got it from Dell. Any documents and added programs will be formatted away.
I have an Inspiron 518 desktop, shipped in 1/09 - running Windows Vista HP 64 bit.  I have some minor Registry problems that involve mostly programs preinstalled by Dell, and was considering reinstalling Vista.  Then I found the info about PC Restore on journal ID: 10300RVLTJ, article 336966. It appears to apply to my Inspiron, as it was shipped prior to 4/09, after which  DataSafe Local Backup was installed regularly. Is it possible that running PC Restore would restore the Vista registry to it's original state?  This would save me some time over reinstalling Vista.  Thanks!
Does Dell Factory Image/PC Restore fix Vista Registry?