Ok- I know very little about computers so i will try my best to make this understable to someone who does. i recently received a free computer from a friend. its pretty old. it's an ibm aptiva. my problem is windows. it shows that windows is installed but when i try to access internet it asks for the windows95 cd rom. i dont have and called all over town and no one has it. or 98. now i get a black screen that says invalid system disk. tried rebooting it and cut out power and it still says it. any help at all will be greatly appreciated. thanks.