Motherboard problem or something else

[Larry04]

Hi. I purchased all my parts and they are compatible. When I hook everything up, I double checked to make sure everything was correct but when I turn on the computer, the monitor has a "No Signal Detected." I thought it was the motherboard giving out no signal because my mouse and keyboard never light up when it started so I RMA'd it through newegg. The new motherboard came back and I've checked everything once again but i still get "No Signal Detected." All fans are running (PSU, Cpu Heatsink, and Videocard fan) Everything powers on and I only placed 1 ram stick. What is the problem?The monitor works on an older computer though. Thank you.

1. SAMSUNG 22X DVD±R DVD Burner with LightScribe Black SATA Model SH-S223Q - OEM

2. Antec Three Hundred Black Steel ATX Mid Tower Computer Case

3. Western Digital Caviar Black WD6401AALS 640GB 7200 RPM SATA 3.0Gb/s Hard Drive

4. ZALMAN CNPS9700 LED 110mm 2 Ball CPU Cooler

5. XFX HD-485X-YDDC Radeon HD 4850 XXX 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card

6. GIGABYTE GA-MA790X-UD4P AM3/AM2+/AM2 AMD 790X ATX AMD Motherboard

7. Patriot Viper 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model PVS24G6400LLK

8. CORSAIR CMPSU-450VX 450W ATX12V

9. AMD Athlon 64 X2 7750 Kuma 2.7GHz 2 x 512KB L2 Cache 2MB L3 Cache Socket AM2+ 95W Dual-Core black edition Processor

 

[Tmagic650]

Have you connected the power supply to the motherboard 6 or 8 pin connector near the CPU? Make sure you haven't used a PCI-e connector in that CPU power connector