Here are the things that I ordered:
Case: XCLIO Windtunnel Fully Black Finish 1.0 mm SECC Chassis ATX Full Tower Computer Case - Retail
PS: XCLIO DIAMONDPOWER 880W ATX12V / EPS12V SLI Ready CrossFire Ready Active PFC Power Supply - Retail
MB: GIGABYTE GA-790XTA-UD4 AM3 AMD 790X SATA 6Gb/s USB 3.0 ATX AMD Motherboard - Retail
CPU: AMD Phenom II X4 955 Black Edition Deneb 3.2GHz Socket AM3 125W Quad-Core Processor Model HDZ955FBGMBOX - Retail
RAM: OCZ Gold 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Low Voltage Desktop Memory Model OCZ3G1600LV6GK - Retail
HD: Western Digital Caviar Black WD6401AALS 640GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
Video Card: XFX HD-587A-ZND9 Radeon HD 5870 (Cypress XT) 1GB XXX Edition 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFire Supported ... - Retail
Monitor: SAMSUNG 2494SW Glossy Black 24" 5ms Widescreen LCD Monitor - Retail
The RAM and Motherboard don't work (at least I think so). Is that true and are there any other problems I should fix now?
I know this seems like a lazy person asking you to do stuff but I already screwed this up once and I really just want to get it right, it's a lot of money for me.