I have windows 7 64bit home edition installed on my semi-custom gateway dx4200-09
9 times out of 10 when i go to boot the system from completely off to regular windows it will first go to the gateway boot up screen and then a black screen with a small flashing cursor in the upper left hand corner of the screen and thats it it won't boot or do anything
if i turn it on and off a few times eventually it will boot up and everything will be fine and dandy.
I would really like to know what is wrong because it is really frustrating. When this computer was purchased it had vista 64 bit and i upgraded to win7 throught the free upgrade system and my copy of windows is completely legit.
Run a scandisk. I recently came across something similar with a laptop (Toshiba) and Vista on. Apparently the system loses connection to the peripherals from time to time (controller) and hence does not find a suitable device to boot and just hangs there with that cursor you mention on the top left blinking. If that does not help, try reflashing your motherboard BIOS.
Not PSU and I dont think drivers - you really havent made it to boot yet..
Im guessing there are a number of issues that cause this - as darkguset mentions. When this happens to me - I have USB boot enabled and I have a USB drive inserted. There is no boot loader on the stick so it hangs...just like you describe.
Make sure USB boot is off, network boot is off and the peripherals are set up properly. Disable ports you arent using - you may have already done that. Otherwise I never reach that same hang point and the system boots every time (with ATI drivers)