As with any PC, do a scandisk and a defrag. I believe you have either a corrupted file or possibly a corruption of the CMOS telling the control how to read the mass memory device (hard drive, DOM)
Corrupted files are saved as FILE0001.CHK (EXAMPLE). I then look at the corrupted file in edit to see what it was. Based on what I find, I may nuke the device, format, load DOS, software and machine parameters.