ATI X1800 malfunction with flagpoles on gaming

I have a Alienware Area-51 5750 and it has Ati 1800 in it.
17inch notebook with duo core 1.66 1gb
Also im using xpmediacenter 32bit


So yeah im having the sae troubles with the poles or like stick figures.
except i dont see them unless im playin games. wen i watch movies or
anything else im fine.

Halo runs fine with no erros messages and very minimal poles just like
battlefeild 2. except battefield 2 doesent even show any. This lead me
to assume that only games with high demand did this. because playing unreal3
at first was fine but then the Poles start to come then i couldnt even get to '
main menu with the computer crashing

So i did reinstall xp just to din out the problem still exist also went to
Aliemware.com were they have the most updated drivers. downloaded
the recomended 1s advise by customer service and still no change.

So yeah idk what the problem is. the x1800 is a 256video card so there
shouldnt be any problems. Theres is 1 thing. everytme the error message
happens it always suggest the i check a cable???? idk what the problem is
Also i try tweaking the card it self in ATI Catalyst. still didnt get a result

But if som1 does im all ears