Sequences/songs won't save! Losing samples too!

I have an MPC 2500 w/ 80 GB hard drive installed and 128 MB RAM. When I go to save "ALL SEQ AND SONGS" it tells me I already have a file with that name, so fine, I hit "replace" and another black box pops up saying "file name exists" and will not allow me to replace or even rename. In effect I can't save songs. When I direct record or load a sample from a CD and go to save, it tells me file already exists, when I'm 100% sure it does not. I will however aloow me to "replace" in this instance. Also, when I save the entire project, when I reload, the samples do not come up with the program. I have to load the program seperately "with samples" in order to get it to work. Has this happened to anyone, as I've had my MPC for about a year with no problems of this sort before. Please help!

Try updating or reinstalling the OS.

Reinstalled OS & re-formatted hard drive. No luck.