I bought an external 250 gig about 2 years ago. Recently it just stopped being recognized by my iMac and my Macbook. Sometimes it shows up in Disk Util and System Profiler sometimes it doesnt. There are a few files I need off of there and if I can just get those it would take maybe 10 minutes of transferring. Ive tried Drive Genius and it doesn't recognize it. Is there anyway I can repair this without paying big money?