On the surface of this, it seems like you have an actual bad data sector on your harddisk, and you may indeed have to run chkdsk to see if you actually do have any bad sectors on your harddisk. The flip side is the file may have just been corrupted during your second Poser installation - this file is apparently the one responsible for storing the serial number for your product. If poser can't read the file, it'll keep asking for your serial number. You MAY be able to delete this file, and once Poser starts again and asks for the serial, that might be the last time it asks, because it MAY just recreate the missing file automatically. To test this theory, try renaming or moving the bad file somewhere else, and then restart poser. If it asks for a serial number again, supply it. Then close poser again and restart it once more - if it starts without asking for the serial or giving you the error message then problem solved. Finally, if all this fails - well, you may have to reinstall poser 5 again - but make absolutely sure that all remnants of your old install are gone. The only other thing I can think of is to look on the install CD and see if you can just copy a new version of this .dta file over the old one. Hope this helps more than it confuses! Jack