Mouse Dragging in FullScreen

[os79]

I have maddening problem.
I had been days at it.

Well, first my specs:
Windows Vista 32-bit
Acer Aspire L5100
Athleon x2 64 4400+
3gb ram
2.3 ghz
320 gb hd memory (170 of it for Vista, the rest for Data)
radeon x1250 (integrated)

Here is the problem (and it startd only few days ago, NOT BEFORE!)
My mouse suddenly started to drag badly in full-screen. I went to windowed play but the map drag in there and it is not pretty.
I even set my graphics at lowest (like I said, I had been at it days with many solutions but no joy).

So any ideas?
Thanks!

EDIT:
Plus I'm playing Beyond the Sword mods. But even vanilla BtS has bad mouse movements.