|I you still have the sticker that came with the computer that contains the installation key then there shouldn't be a problem providing you do a clean install and not try to install over the existing installation. That means deleting all partitions and starting again from scratch. The Installation disk should do that for you.|
It matters little what the Service pack is, you can always install the latest service pack after the OS has been installed. However bear in mind that SP1a will not recognises a hard dsik in its entirety bigger than 132 Gbs. You need SP2 for that and a 48 bit compliant BIOS. SATA could be a problem but I doubt a computer that old has a SATA drive.