opengl all screwed up...

guys i need some help fixing the opengl in my puter it got screwed up when i installed cs 1.6 beta, i keep getting this error in some games and some 3d graphics applications - "the selected mode is not supported by your graphics card".
one solution is to turn hardware acceleration of, restart and the set hardware acceleration to full again. but this getting to be really annoying.
i tried reinstalling drivers, updating all drivers basically everything short of formatting my HDD, which i cant do atm coz i got so much stuff on the pc which have to be sorted out.
i was hoping that maybe any one of you guys could recommend a solution (something which i might have overlooked).

here are the basic specs of my pc if it helps:-
P4 1.5Ghz, leadtek GF4 Ti4200 128mb (44.03 det drivers), 256Mb RDram, win xp w/sp1, sb pci 128.

any help would be greatly appreciated .

[§ôµÏG®ïñD]

Run games in D3d.. You could try getting the opengl drivers and seeing if they help or do anything at all.

half life sucks under D3D, framrates are horrible textures get all crappy so its not really worth it.
btw where can i get the oGL drivers, i tried opengl.org but all they had was the ogl95.dll, i tried leadteks site and found nothing.