Hibernation hangs; strange event in log

I always use hibernation, never had a problem with it up until today.
When I tried to start the computer, the "Windows is resuming" screen just sits there...indefinitely and the green progress bar at the bottom is extremely slow.

I tried deleting the hiberfil.sys file and re-enabled hibernation, but the same problem keeps occurring. So I started browsing the event logs and I found that every time I hibernated the system today I got an:

The previous system shutdown <at time/date> was unexpected

error.

Which is strange as it was not unexpected for me, I initiated it.
What could be causing this?

Do you have something running in the background that could cause hibernation to pause? Have you scanned for Trojan Horses? Try Trendmicro free scan.

I had already scanned with Windows defender, spybot and Avast antivir. I did another on-line scan during dinner, but no positives.
There is another thing I just noticed, not sure if it is related. In explorer I suddenly have a Floppy drive listed while there is no physical floppy drive in my pc.
I remember seeing it this afternoon, but it didn't register in my brain until just now that it is new and not right.

Yesterday morning I put the computer into hibernation like always, it worked (as always) yesterday afternoon, but today it hasn't worked one time (and I tried a lot!).
I do not remember installing or changing system settings yesterday (which is not to say that I might have).

I would start in the BIOS and check the power settings and then reset them in Vista.

I did that last night a few times (I tested the S1/S3 settings in my BIOS) but it didn't work. The last thing I did was reset my BIOS once again, and I was to tired to try it out properly so I put the computer in hibernation and went to bed, this morning it started ok, and according to the logs it ran a backup and a defrag during the night, so the problem seems to have resolved.

Thanks for the help.

There was probably a task running in the background that caused this error. Vista has a habit of running task every so often. Go into your task scheduler to see if there is anything factory set in there. This may stop the problem re-occuring.

Well, I went through all tasks and logs meticulously, but found nothing that might cause this...however, I did notice that the backup last night ran at 3 o'clock while it is scheduled to run at 1. So maybe it took windows to resume 2 hours from hibernation, in which case it may have been a defrag problem as the defrag ran after the backup and now the problem is gone.