Bitmap Error

Hello to all,

I would really appreciate any help with this issue.
I'm using Coreldraw X3,operating system, Windows XP Professional version 2002, 1GB of RAM,free space of 4.56GB on C drive, 34.8GB on backup drive,display adapter Radeon X300,HP compaq dc7600 convertible
I'm having a lot of difficulties opening a series of files. I had been working on a laptop for a few months and upon returning to the office I tansfered the files to my desktop to complete thr final revisions. I worked on my desktop for 3wks without no problems and then one day I went to open the files and recieved this message on all of them:
"Error reading a bitmap in file"
I have since tried numerous methods with no success. Do you have any suggestions. I don't particularly want to redo 100 hours of revisions again! I'd GREATLY appriceate your help!!!!