There are 2 basic types of hard drive that most people will want to install. They are 1 - Pata, also called ide and ata. Easy to recognise as they have a large 40pin socket and jumper settings. And 2 - Sata, both sata 1 and 2 are set up in the same way. They are easy to recognise as they don't have a 40 way socket but have a 4 way instead. There are also scsi hard drives but i doubt may people will be using them so i will not be dealing with them in this post!! Pata - Pata's will connect via a 40 way data cable that has 2 plugs on it excluding the one that plugs into the mobo. It is VERY VERY important to get the jumper settings correct or THEY WILL NOT WORK!!!! There are 3 basic jumper settings, cable select, master, and slave. The easiest way to set them up is to use cable select. The mobo itself will then assign master and slave as it sees fit. Usually it will set the drive on the end plug as master and the other one as a slave. If you are running more than 1 pata drive on the same cable then you must insure they are both set to cable select or that 1 is set to master and 1 is set to slave. Having both set to master WILL NOT WORK, and having both set to slave WILL NOT WORK. Once that is set correctly most mobo's will be happy and boot fine, if yours doesn't then you will need to check the bois settings. The instructions for doing this will be in your mobo manual!!! Sata - Only 1 device is catered for per cable so there is no need for jumper settings. Its just a case of making sure your bios picks it up correctly, again, you will need to refer to your mobo manual for instructions. If, after properly installing your hard drive and checking the bios out it still doesn't show up in windows then it probably requires formatting. For windows XP Pro, right click on your "my computer" and select manage, storage, then disk management. Locate your new drive on the right hand side and right click and use the format wizard. Once all that is done you should have a new hard drive installed and working properly!!! Enjoy!! P.S. I only have XP Pro so if anyone else can add the formatting procedure for other windows versions then please feel free to do so.