My Games are BROKEN D: Help?

[Stepper321]

Hey guys, i just reinstalled windows. And now when i play a game. I get weird models. I got some images from Counter Strike Source that some part of the models are missing. I also have upgraded my Video Card drives twice. And i don't know what's wrong more.
Theres even text screwed up. And it's not only Counter Strike. It's for every game that's 3D. So amnesia too.
I also get a MASSIVE lag spike every 5 seconds.


Here are 3 pictures:

Spoiler below!

Weird Toilet Model.


Missing Parts of the gun.


Missing parts of the character.

Here are my PC specs:
Microsoft Windows 7 Ultimate
6.1.7600 Build 7600
Systemmodel G31-M7 TE
Systemtype Op x64-gebaseerde PC
Processor Pentium® Dual-Core CPU E5300 @ 2.60GHz, 2599 MHz, 2 core('s), 2 logic processor(s)
SMBIOS-version 2.5
RAM 4,00 GB
GPU ATI Radeon HD 4300/4500

Help Pretty please. I can't game anymore.