Computer Problems. HELP!

[blageo23]

The desktop at my house is being all retarded. Its the one we use for printing and stuff from out network. This is what happens
Turn the computer on. it comes to a black screen that you can select regular windows or safe mode. Either one you go to after you click on it a blue screen pops up it reads
"Problem has been detected and windows has been shut down to prevent damage to your computer
UNMOUNTABLE_BOOT_VOLUME
If this is the first time you've seen this stop error screen, restart your computer. If this screen appears agian, follow these steps:
Check to make sure any new hardware or software is properly installed. If this is a new installation, ask your hardware or software manufaturer for any windows updates you might need.
If problems continue, disable or remove any newly installed hardware or software. Diable BIOS memory options such as caching or shadowing. If you need to use Safe Mode to remove or diable components, restart your computer, press F8 to select advanced startup options, and then select Safe Mode.
Technical information:
*** STOP:0X000000ED (0X827E6868,0X0000006,0X00000000,0X00000000)

There was no recent install of any programs or software. We dont even really use this computer. and Safe Mode wont work either. Any help will be great