WCollins,
Are you running a Soundblaster Sound Card? SB Drivers known to cause that very problem too.
Try downloading the latest drivers for your Motherboard, Video Card and all your PCI cards.
Take Care,
Richard
P.S. If you do have Soundblaster, you can disable Legacy Support for it in the Device Manager and that will shave about 30 seconds off your boot time as well as help with the shutdown too.