Shut Down Problem

On Vista Home Premium, my computer shuts down just fine, but if I had my
computer in sleep and then shut-down later after bringing it out of sleep,
then Vista's shut down slows to a crawl. When I shut down, the sidebar
disappears, then the computer just sits there and idles for three or four
minutes as if it were not going to do anything, but after a while, it will
shut down. There are no error messages or anything when this happens. I
suspect since it only happens after I would resume from sleep, that it might
be some sort of driver issue, but I have no clue which one although I have a
few suspicions. Thanks.

-Specs-
AMD Sempron 2800+ OC'd to 2GHz (Socket 754)
Asus K8N motherboard
NVIDIA nForce Networking Controller
1.5GB of RAM
WD 120GB 7200RPM IDE 8MB cache HD (Vista)
WD 80GB 7200RPM IDE 2MB cache HD (Storage)
Lite On 16x DVD drive
Memorex 52x32x52 CD-RW drive
3 1/2" floppy
Ati Radeon X1600 PRO video card with the latest driver
Creative Audigy with the latest *beta* driver. (This is what I suspect as
possibly being the problem.)