Well.... Ill make this short lol.
I want to factory restore this desktop & its jist not happening
I press f8 on boot and it brings up additional options but none help restore. I have no install discs either. Simple quick fixes? What is make/model of computer?Dell inspiron 531sThe Inspiron 531s did not ship with a restore partition.
Source: http://en.community.dell.com/support-forums/software-os/f/3524/t/19335211
Jesse from Dell

To double check try this from the manual, which also says
NOTE: Dell PC Restore by Symantec (XP) and Dell Factory Image Restore (Vista) may not be
available in certain countries or on certain computers.

Windows Vista: Dell Factory Image Restore
1 Turn on the computer. When the Dell logo appears, press several
times to access the Vista Advanced Boot Options Window.
2 Select Repair Your Computer .
The System Recovery Options window appears.
3 Select a keyboard layout and click Next .
4 To access the recovery options, log on as a LOCAL USER. To access the command
prompt, type administrator in the User name field, then click OK .
5 Click Dell Factory Image Restore .
NOTE: Depending upon your configuration, you may need to select
Dell Factory Tools, then Dell Factory Image Restore.
The Dell Factory Image Restore welcome SCREEN appears.
6 Click Next.
The Confirm Data Deletion screen appears.
7 Click the checkbox to confirm that you want to continue reformatting the
hard drive and restoring the system software to the factory condition, then
click Next .
The restore process begins and may take five or more minutes to complete.
A message appears when the operating system and factory-installed
applications have been restored to factory condition.
8 Click Finish to reboot the system.

You can download the manual from the link in the 2nd post here
http://www.geekstogo.com/forum/topic/326447-resetting-to-factory-setting-with-no-disk/