Name = Intel (R) 82915G/GV/910GL Express Chipset Family
Manufacturer = Intel Corporation
Chip Type = Intel (R) 82915G/GV/910GL Express Chipset
DAC Type = Internal
Approx. Total Memory 128.0 MB
Current Display Mode = 1024 x 768 (32 bit) (75Hz)
Monitor = Plug and Play Monitor
Your problem is that you're trying to run a 3D game on an integrated chip.
99% of all modern games require a special technology called Hardware Transform and Lighting. Without this technology the graphics chip has to do a lot more work to get the same effect and it really slows the computer down because the graphics is trying to make a special effect that it can't make.
Almost all modern graphics chips come standard with this technology but integrated chips in cheap laptops and 'home office' desktops don't include it because the computers they come in are expected to do basic stuff like photo uploading, web surfing or document writing, not gaming.
I'll put it in short terms:
Problem: Your computer can't play TF2 or any Source game properly without a lot of lag.
Solution: Get a new computer that has actual graphics power, not a free one.
Also CPU stands for Central Processing Unit, aka a Processor.