Random turning problems

Occasionally, my turning (which is right mouse/A, D) will get screwed up, where one direction just doesn't go, and the other goes way faster than it should, **** up my play pretty bad.

My specs, according to XFire:

Manufacturer:
MSI
Processor:
AMD Athlon(tm) 64 X2 Dual Core Processor 4400+, MMX, 3DNow (2 CPUs), ~2.3GHz
Memory:
3072MB RAM
Hard Drive:
320 GB
Video Card:
NVIDIA GeForce 6600 GT
Monitor:
Plug and Play Monitor
Sound Card:
Realtek HD Audio output
Speakers/Headphones:
Keyboard:
Logitech EX 100
Mouse:
Logitech EX 100 Optical Mouse
Mouse Surface:
Operating System:
Windows XP Professional (5.1, Build 2600) Service Pack 3 (2600.xpsp_sp3_gdr.090206-1234)


My computer does pass the minimum requirements.

P.S. Also, how can I adjust the speed at which A and D turn?

EDIT: Also, it's fixed by resetting my PC. I just don't want to every 10 minutes.