CMOS Error

Here's the set-up:
Late November I used an external drive to try backing-up some files on my desktop comfuser (it's usually used on my wife's laptop). I removed it correctly & all was fine the next day. We then went on vacation out-of-state (11/23-11/27); so I not only had the comfuser shut-down (as usual), but I also turned the comfuser's PSU power switch OFF.

Since coming back, when I 1st boot-up & as the POST is listed, I get this message:
CMOS checksum error - Defaults loaded.

Then right after I get:
Press (Ctrl+S) or F4 to enter RAID utility.

A few seconds later, the comfuser lists the POST again (really fast) then boots normally. Normally except for 3 things:
1. I sometimes get the "Windows needs to install driver software for your Unknown Device" dialog box. Which I click "Don't show this message again for this device" & enter my password (twice).
2. My clock is ALWAYS reset to Jan. 1st, 1996; which also gives me an Invalid Certificate message if I try going online & forget to change the clock 1st.
3. My 'alphabet soup' is now all jumbled-up. HDD is still C:, ODDs are still D: & E:; but my media card reader, USB ports & printer have been mixed-up a little.

I have always had only 1 SATA HDD & 2 PATA ODD & have never even tried a RAID set-up. The external drive has a USB cable. I went through my mobo's settings & no RAID is set-up & the HDD is the only drive set to boot. I don't know if this is a software/hardware problem, but can anyone help me w/this?