Glenda,
As someone already said - contact the manufacturer, or at least read the
manual for the PC you have which is most likely available on their site if
you don't have a paper copy..
Something you may want to try, is looking at the screen real close when it
first boots up. You may see a message that states, Press F1 to enter Setup,
Press F2 to Enter Diagnostics / Repair / or other words that indicate you
can enter into a restore partition of the hard drive. A lot of
manufacturers partition off a small section of the hard drive and store the
necessary files (CAB files) and routines that will reinstall all your
software and the operating system back to factory fresh condition.
You didn't give us much information to help you with, like make and model of
the computer, why do you feel you need to uninstall the OS, which version is
it - Home or Pro, original, SP-1 or SP-2. Has windows "Restore" been tried?
Do you think you have a virus or a worm, what AV program are you running?
Sometimes you can use on-line Chat with the manufacturer to troubleshoot a
problem or use the Knowledge Base and FAQ sections to solve problems.
Bob S.