Source engine lock up on my x1400

Hello, please help!
I have a dell inspiron e1505 runnning an x1400 256mb vid card. 1 gig of ram
and Core 2 duo 2ghz processor.

Earlier this month I downloaded DOD source and Half life 2 episode 1 off of my steam account. I played episode 1 first and the first thing it told me was to update my drivers. Unfortunately, the dell site doesnt have the most recent drivers for the x1400 and if I try to download the latest cats off the ati site, it tells me it isnt compatible.

So i tried playing it with the old drivers anyway and 3 minutes into the game it froze with looping noises. I had to reboot and decided to try again. So i tried many times and the game would always just randomly (in no fps intensive areas) lock up and i would need to hard reboot.
Anyway, i decided to try the latest Omega drivers as they were more up to date. Awesome. THey worked and i made it through most of episode 1 without any more freezes. I still had it freeze up 3 or 4 more times with the omega drivers around the end of the game. I was running everything default (defaulted to high settings) on 1024x720, and would get around 50-60 fps.

So then i try dod source, and even with the default settings and good fps (50average-150 when looking at the sky), I get a lock up every time i play. Even with everything turned down and the res at 800x600, it still locks up. HDR is turned off and even toggling the settings doesnt stop it from locking up. Sometimes I even get a blue screen, but I always have to hard reboot my laptop. I dont get it. HL2 plays Perfectly fine! Max settings (no AA) and all. DOD source has good fps and looks really good until it randomly locks up. I dont know what to do i want to play the game and my system can obviously run it well until it has this problem... It is very frustrating. Does anyone have this same problem? I need a solution. THank you very much.
Zach