I recently got a Sabertooth 990FX R2.0 mobo to replace my 890FXA-GD70 that stopped working. I can't get the new mobo to work. The boards stanby led stays lit in green. The cpu, ram and boot device led's never light up.I've tried 2 different cpu's (Phenom 2 965 & 1100T), 2 different psu's (ZX 1250W & Corsair TX 750 V1.0), 2 video cards (HIS HD 6950 & XFX HD 5770), 4 sets of ram (Kingston Hyper-X 1866 & G-Skill Ripjaws 1600 -in single & dual 4gb. sick configs- tried al ram slots) & my ssd (Vertex 3 MaxIOPs 120 gb. & 2Caviar Black 1.0 tb. 32mb. cache -each by themselves in sata port 1). All thes parts are in working ordder and have been tested. Could it be that my Microsoft Wireless Desktop 200 is the reason, as both are usb 2.0 w/single plugin for both ?