Ok what may have happened prior to you re-installing Windows is you had 2 drives, both either FAT32 or both NTFS format. When you reinstall XP you are given a choice of what type of file system to use. If you didn't know what type and chose randomly there is a chance you now have 1 drive with FAT and the other with NTFS. When this happens the operating system won't be able to read the storage drive. Go the C drive, right click and go Properties, it will state what File System it is. You now have 3 options, reinstall XP and choose the other FS, try and convert your storage drive to same as OS or remove drive and plug into a spare/mates PC copy all data off, reformat to same as OS and then copy back on. If u are not that technical go for option 1.