I have some .psd files saved onto disc and whenever I put a copy of them onto my harddrive and open them up in Photoshop there's no problems but today I went to open one of them up in Photoshop it said that it didn't recognize the file. Why would this be happening now? It only does this to the .psd files that I burnt onto disc. I even tried opening them up in ImageReady and it wouldn't work.

Oh, I don't know if this is needed but I'm using Windows XP.

Did you change the file association for .psd files? Right-click on one of the files in Explorer and click Open With and select Photoshop.

No I didn't. When I open them up in Photoshop it won't even show me a small preview at the bottom of the Open screen.