video files dont display properly

hi, since my last OS reinstall at the beginning of the year, when i play any video file the colour is really bad, it's monochrome green. this happens with all my media players. what should i do? get some new codecs? or do i need a driver? i think i might download a program called GSpot.

Features:
· Determines which video codec an AVI file uses
· Determines what audio encoding method the file uses
· Determines what codecs you have installed, and whether you have the one needed
· Up-to-date database of over 200 codecs, including the latest DivX 5 and XVID systems
· Shows reported audio bitrate and calculates video bitrate
· Reports if the file is truncated, and how many bytes are missing. Great for downloaders.
· Identifies MPG, MPEG, MOV, WMA, WMV, ASF or OGG/OGM if an unknown non-AVI file is examined.
· Shows RIFF INFO (title, etc) if present, including hidden ASCII in the "JUNK" field
· Easy to use ("File > Load" and you're done)
· Microscopic footprint - download size only 29KB
· Free for personal use
http://www.headbands.com/gspot/download.html
http://www.softpedia.com/get/Multimedia/Video/Encoders-Converter-DIVX-Related/GSpot.shtml
what do you think about GSpot, is it what i need?

i have Everest and PC Wizard too, they can tell me everything i need to know about my computer, i'm just not sure what it is i need to know. can you help?
thanks