When I lower my gfx settings I get a error message and gmod crashes.

I’ve been trying to play on my server for the last hour and i’m just getting a shit load of lag. I’ve tried to lower my gfx setting because we use gm_bigcity and i have had lag problems before with it (when i had my other pc, what died over the summer)and it was just because of my gfx settings being to high. When ever i lower them and hit apply i get.

 "Garry's Mod: hl2.exe - Application Error" "The instruction at "0x11cdc04d" referenced memory at "0x0eac0454'. The memory could not be "read".

One of my friends told me to lower my dxlevel and i did, but i still get the same message when i try to lower the settings.

Here is my specs:

 Gateway GateWay M210 and 3500 Series Intel(r) Celeron(r) M processor   1.30Ghz  1.29 Ghz, 480 MB of Ram. gfx Intel(r) 82852/82855 GM/GME Graphics Contoller. Windows xp Home edition Version 2002 service pack 2

Is It just that this laptop is just not meant for a game like this, or is there something that is wrong?