Hey there adu, sorry I haven't been on this site for a little while. First off, Lookin's posts are dead on concerning Install/Restoring the operating system if you go by the route of using the discs. In reply to your last post, if you don't make an image of your drive using software such as Ghost or Acronis, and you reformat your computer, then you better have the XP/Vista install disc to re-install the operating system. If you don't have the install disc, then you'll either need to get the imaging software to make the "copy" of your hard drive to another one, otherwise, you'll find yourself purchasing a new copy of the OS. Also, the install disc for the OS is NOT the disc that will install any other software BUT the OS. It does not have Microsoft Office or any other program on them. You mention that you may have discs(more than one), if that is true, you will need to read the labels on them to see what they contain. If they say that they contain other applications such as Microsoft Office, then those are the install discs for those programs. They will say "Install program" on them if they are. And yes, if you have a TRIAL version of Office 2003 and want to upgrade to the FULL version, then you have to buy it, you can't get it for free(unless your some sort of hacker, but then, that's illegal, LOL). My advise to you is this, if your not sure what your doing with these processes, then I suggest you get a local computer tech to help you. Look in your local phone book, you be able to find someone that isn't too expensive. Going to places like Best Buy's Geek Squad will burn a big whole in your wallet, so call around to see what people would charge you.