WIn 7 64 Ultimate - Freeze on screensaver

When I leave for an extended period, and come back, and bring the computer back from turning off the monitors, my system freezes for a minute or so, then functions resume. List of things I thought it could have been:

• Having 4 network drives mapped
• USB Devices in "sleep mode"
• Network adapter in sleep mode
• Virus
• Rootkit
• Changed power settings (nothing spins down, nothing goes to sleep).

I searched via Google and found similar issues, and tried all of them, and nothing works.

System specs -

• i7 870
• 16GB Patriot DDR3
• Asus p7h55-m
• gtx 295
• 3x Seagate 1.5TB HDD

And the reason it froze was because...

My taskbar was on auto-hide. This is up there with system lockups in Photoshop because I didn't have Aero enabled.