Half Life 2 and Force Ware issues

Hello everyone!

I've got a situation. I have been playing Half Life 2 without any problems (retail version) Recently I was urged by Steam to upgrade Forceware drivers version (77.72) to the most recent one (77.77) in order to play. Mind you I've been playing this game for the past month without any problems at all resolution, frame per sec, no slowing down; evrything perfect after I upgraged to my new version it was good for the next 4 days and then it happened. The game freezed up and I had to reboot, after it reboot it wasn't letting me get back into the windows desktop instead it would go straight to the option screen to either start windows normally or start windows from last good known form. It seemed that the game everytime I play it now it crashes and it's really annoying me.
So my question is how can I get rid of the old drivers and use my old working version drivers in a safe way. Because my computer is having a lot of problems now.

Here are my sys specs:
CPU - AMD Athlon 64 3200+ 2.0 GHz Venice core<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

Motherboard - MSI KN8 Neo4 Platinum nVidia nForce4 Ultra Chipset serial ATA150<o:p></o:p>

Ram - Corsair TWINX 1024-3200C2PT 1GB DDR400 w/ heat spreader <o:p></o:p>

Hard Drive - Western Digital Caviar SE WD2000JD 200GB ATA 7200 RPM<o:p></o:p>

Video Card - VGA EVGA GF 6800GT 256-P2-N376-AX<o:p></o:p>

Sound Card - Creative Labs Sound Blaster Audigy 2 Value SB0400 &.1 Channel PCI<o:p></o:p>

Operating System - Windows XP Home w/ SP2<o:p></o:p>