I bought a computer from my local Goodwill Store (The section that deals only with computers and computer related parts, etc.) and now after a year and a half I get a message on my screen saying that the dealer install of Windows XP Professional is now not authentic. I could fix the problem with a new install but I am taking online college courses and the remainder of my homework is due tomorrow. This problem has already cost me my entire English Thesis Paper that will have to be redone not to mention the remainder of my work that would not have been a problem turning in on time until this fiasco of a problem!! The store is of no help and we ended up into words that now have burnt a bridge that didn't matter. They put a coa sticker on the computer when they refurbished it to Windows XP Professional but left out half the numbers to correct the problem. I hate to do it but I have other computers with Windows XP Professional with the complete COA sticker on them if I only knew how to fix the problem. I have called Microsoft and they are rude and definitely of no help. All they want is for me to buy Windows 7, they claim that they don't even help with technical support on Windows XP unless I can provide all the information. I hate them!!! They only want to sell you something you don't need yet when you don't have the money. I am running a Dell Optiplex 330 with a dual core processor (2.0 GHZ each) and I have 4gb of RAM installed with a good video card with 1gb of dedicated video RAM. Please help me with a fix or I will get 0's on the work that I need to turn in and this will ruin my grades in my classes while I am trying to better myself. I don't care how I just need a fix. Please anyone who can help, I am in your debt. I believe I just need to somehow enter a correct Win XP Professional number so it will validate it. I have valid numbers for Windows XP Professional from other computers I have parted out.