Hello

I bought my computer beginning of 2012. Around November it started overheating and I sent it back in and they 'repaired' it. Whatever they did didn't help and it kept on overheating.
This means I never close the side of my PC anymore, and during warmer days I'll put another fan close by blowing into my case.

I'm doing this at the moment, but can barely play 5 minutes of Bioshock before my CPU reaches 85 degrees and my pc shuts down.

There's not too much dust in my case...

Why? All my fans are working - CPU fan running at 3300 rpm, chassis fan 1 running at 1000 rpm and chassis fan 2 running at 950 rpm.

Here's my specs:

PC Case: NZXT M59 Gaming Case
Power Supply: Corsair 500CX Builder Series 80+ Power Supply
Processor: AMD FX 8120 Eight Core Bulldozer CPU
Heatsink & CPU Fan: Standard Heatsink & CPU Fan
Motherboard: ASUS M5A970 970GX AM3+ SATA 6Gb/s USB 3.0 MB
Memory: Corsair Vengeance 8GB DDR3 1600Mhz High Performance RAM
PCI-E Graphics: NVIDIA GeForce GTX 550 Ti 1GB 192bit DDR5 Overclocked Card
Sound Card: Integrated 8 Channel HD Audio
Primary Hard Drive: 1TB Seagate Barracuda 7200RPM SATA3 6.0Gb/s Hard Drive
Secondary Hard Drive: 2TB Hard Drive