A disk read error occurred

How bad is it when you see the above upon start-up and nothing else happens. When I put in the XP start-up disk, it see's the hard drive b/c the "new" install wants to format the partition. Is there any way to save the data that is on the hard drive. Once I can get to c prompt, and try to look into the dir (C:\>DIR) I get the following message: "An error occured during directory enumeration". Can someone PLEASE HELP ME SAVE MY HARD DRIVE INFO