Make sure any jumpers are set properly and that your CPU and RAM have already been installed. Most of today's newer mainboards don't have hardware jumpers, the CPU's Speed/Voltage/FSB settings are all automatically set via the Mainboard's own 'soft jumpers' (located in the BIOS). If you do happen to buy a Mainboard that requires jumpers to be set, refer to your Mainboard's manual, it will guide you through proper jumper setup procedures.

Depending on the quality of your case, you may be lucky enough to have one with a detachable Mainboard installation plate. Having one of those babies makes it much easier to install or remove mainboards. Second, you'll want to check and see what actually connects your Mainboard with the installation plate. The most popular (and probably best) method is the use of metal risers. These screw in and out of both the Mainboard and the case, providing a good safe hold on the board. The second method is that of using plastic spaces. These snap in and out of your Mainboard, but are often easy to break, and can be hard to use.