I'm running Windows 7 RC x64 on a Dell Optiplex 755, here are the specs that are relevant: Intel Core 2 Duo E6550 @ 2.33GHz 4.00GB RAM ATI Radeon HD 2400 Pro After I lock my workstation, I intermittently am presented with solid black screens (dual display) after entering my password to unlock. My screen saver and all power saving settings are disabled. The monitors are not in power-saving mode (power light is illuminated green, not amber), but the displays are completely black. I see this happening about 25% of the time. No errors are being reported in the Event Log (System) which appear to be related (there's a ForeFront error, but it's regarding policy), and the only way I've found to recover is a hard reboot. The keyboard and mouse are unresponsive (no pointer is displayed, CTRL-ALT-DEL is unfruitful). Other than that, great job on Win7!