Gmod Startup Problem (Please Help)

Recently I have installed the latest update but when I went to play gmod it didn’t startup , It start ups then freezes with my cursor as a loading symbol and on the picture, When I go ctrl+alt+del I have my cursor back but the background is still there!Please Help since I want to try out cloud.
P.S I have downloaded the update at a very low speed since I have gone over on my usage.

Specs?

Oops Sorry Forgot
Intel core duo 2.33
4Gb ram
ati radeon hd 4870
Xp sp3

A working link to your Steam Profile would be nice.

Try clearing your dua cache garrysmod/garrysmod/cache (I believe)

Ok Im going to try that now

Profile : http://steamcommunity.com/id/UniteSNinja/

[editline]08:51AM[/editline]

I tried but i didn’t work

You tried lowering your dxlevel? if you didn’t: -dxlevel 81.
The game looks crappy but it should work.

Ive Tried dxlvl,small screen, reinstalling steam and cleaning garrysmod cache. my next try is reinstalling gmod when i get my usage back