Cassielump from what I can see from your pics blown up to 100%.
You have a SATA power wire dangling and a floppy device power plug dangling.
You only have one hard drive so the one that is dangling is ment for a second hard drive if it was installed. (which there is not)
Also you have one SATA plug which appears to have a cap on it, that also is not in use (nor was in use)
Your SATA hard drive which is located at the bottom of the case appears to be hooked up OK.
As you said you do not have a floppy drive installed, so the little white four wire plug is not needed.
I do recommend getting a can of compressed AIR (available at Radio shack or Staples) and blow the dust out of that tower. Specially blow out the dust from the Processors cooling fins and fans.
Any time you use compressed air on the blades of cooling fans I recommend you prevent the fan from spinning.
I also use a narrow long bristle tooth brush for removing dust that remains stuck to fan surfaces.
Any time you mess with any thing in your computer make sure it is unpluged from AC outlet.
Make sure you are grounded to computer case at all times, because your body has enough electrical current in it to wipe out computer components!
Another thing about missing floppy drives. Make sure a setting in your BIOS setup untility was not enabled. It might be called "bootup floppy seek" Not sure what BIOS you have, but that one is commen in most BIOSes. Make sure its not enabled if you do not have floppy diskette drive.
You did not post pics that show the front of your tower or the back so it was hard to see what drives you had in front or why keyboard does work. I assume your using a USB keyboard am I correct?
EDIT: I see that you only have what appears to be a SATA Optical drive in the upper bay area and at closer inspection I see that the floppy drive bay area is empty.
Edited by MrBruce1959, 13 February 2010 - 12:11 AM.