Which O.S. are you trying to install? You should only have to go into bios (boot up screen will usually tell you the key needed for this), set it to boot from CD first, save the settings, put CD in drive and then restart computer. The only problem that would possibly arise is that it is an early version of XP or an O.S. prior to that and you are using a SATA hard drive. You may then need drivers for the motherboard to allow the SATA drive to be accessed. XP gives you that opportunity when it first boots from CD.