I would say it sounds like your file system has been corrupted beyond much hope of recovery short of some recovery service.
If you have access to another computer, you can try buying an external enclosure and checking to see if another computer can mount that drive and give you a chance to pull some data off of it. I wouldn't get your hopes up too high, but we're talking about maybe $20 vs. $2,000 for recovery services if it works. You can also buy a new hard drive at the store the same time you buy the external enclosure... If you can salvage the existing drive, you can just take the newly purchased one back... If it's toast, you are ready with another drive to take its place.
I have a Dell Dimension 2250 running XP Home. I think my hard drive crashed. When I restarted my computer, the window that asks if I want to start in safe mode, start in safe mode with a command line, start with the last good configuration, start normally, etc.
I don't know the exact wording, but no matter which option I choose, the screen goes to the blue screen saying - stop :c0000218 registry can't load the hive (file) \systemroot\system32\config\software or its log or alternate it is corrupt, absent or not writable. It goes on to say beginning dump of physical memory. Dumping physical memory to disk.
It then goes back to the screen where I can choose safe mode, etc. and then goes back to the blue screen. Over and over.
I was able to test the devices through pressing F10 and got some fails on the IDE Disk saying uncorrectable data error or media is write protected. Under the read test I got several a couple being: result code: 0F00-0244, Block 52250682; verify test result code 0F00-1A44, blocks 6393925, 52211711, and 52250682.
I have tried running the windows installation disk, but it doesn't seem to be working. Any suggestions, any tests I can perform? Thank you!