  I know all my info on it is gone and will have to start fresh.   Actually your personal files may not be gone at all. If you know someone with a newer desktop PC with a spare connector to connect up a SATA hard drive, you can slave your hard drive on that PC and get your files off of the hard drive to a USB flash stick.  Otherwise, you can buy a USB enclosure for a 3.5" SATA hard drive like [URL] . You essentially will then have an external hard drive.   Once you get your personal data off of the hard drive, you can put the hard drive back into your C521 and re-install Windows Vista following the instructions at [URL]
I have a Dell Dimension C521 that came with Windows Vista Home 32.  It has been a week today that I killed my OS system.  I tried to do a system restore there was no dates there.  Then I went to something else that told me to put in  Boot Disk because I had damaged files. I had no back-up disk kept telling myself I would do it later.  Yes Hard Lesson learned. Called Dell for help told him error code 0.800 something 1.  He told me to debug hard drive.  My computer does not   have a Boot Manager it is missing. try  to go to  but get Source which I type in for C  and enter code but nothing is recognized. Before I made a Debug disc I wanted to come here first.  I bought  a laptop but I want my desk top back.  I know all my info on it is gone and will have to start fresh. Yes I am one of those, single parent, lost job and have limited funds to work with but was hoping to find people willing to help without having to pay $100 to diagnose and then add up from there.   Thanks  in advance for any help with this situation besides hearing the words again I was a sucker for buying the Dimension C521 because of all its problems. clickchik  
Help Putting OS System Back on Dimension C521