hey guys i need some help, I have stand-alone AutoCAD 2010 install in my PC then my PC needs reformat so my IT reformated it & then i try to reinstall my AutoCAD but the problem it appears this when im trying to re-activate it "The serial number you entered is not valid. Try again. (1)" what is the solution for this do i need to contact Autodesk for a new serial no. so i can get the new activation code or there is simple solution for this...