Steam Problem

Processor: Intel® Core™2 Quad CPU Q6600 @ 2.40GHz (4 CPUs), ~2.4GHz
RAM: 3072MB RAM
Video Card: NVIDIA GeForce 9600 GT
OS: Microsoft Windows XP Home Edition (5.1, Build 2600)

PHX 3
Lifesupport
Gmod Tower
Space Age stuff
Space Build Stuff

I had a problem with my browsers after I removed a virus. So to fix all my browsers, I system restored. The System Restore uninstalled my steam games for some dumb reason.
So I reinstalled them.
Nothing in the folders work now.
By that, I mean like in garrysmod/garrysmod/. Nothing in that folder works. Models, addons, etc.

I tried deleting the garrysmod folder and then reopening gmod to make it again, then downloading everything again.

I need help.