encor3

Hi I'm helping a friend with his very old Latitude d500, it was slower than it should be so I dicaded to reinstall xp pro corprate sp3 x86. Everything went fine uptil the giu section of the installation, then a message apears prompting me to put in the service pack 3 cd. I downloaded that from microsofts homepage and put it in the drive but still the same message. I have tried 10 different cd's, xp home sp1, xp pro sp1, xp home sp2, xp pro sp2, many different pro sp3 and even win 2k sp4 but the same message (but the sp version it asks for changes with the different cd's) I think it's the optical drive that's the problem (firmware or something) anyone have a solution? I'm just curios because now I'm installing xp pro corporate sp3 x86 from an USB-drive so I'm working around the problem Have a good one!