I recently upgraded my system from win7 x86 to win7 x64 and added some new hardware as well (SSD, ram, new PSU). The new setup is as follows:
SeaSonic Modular M12D-750
AMD Phenom Black Edition X2 550
Asus M4A78 T-E
OCZ Platinum Low-Voltage 6GB DDR3-1333 Ram Kit (3x2gb)
Sapphire 4870 SVGA 1gb
INTEL X25-M 160gb SSD
3x1gb WD caviar hard disks in raid0 (dynamic volume)
TP-LINK WN821N usb wireless adaptor
The problem is that I keep getting a BSOD every time I cold boot the system (usually when I load the browser, which is the first thing I do). I have to restart and after that I can use the computer at full load for days without problems. Next time I cold boot the same thing happens.
A few times the problem has been identified on the BSOD as MEMORY_MANAGEMENT or SYSTEM_SERVICE_EXCEPTION pointing to win32k.sys as the cause of the problem. Usually no details are displayed.
I run memtest a couple of times for a few hours. No errors were found.
I switched from Comodo's Security Suite to Zonealarm Extreme Security. Problem continues.
I updated to the latest ATI graphics drivers. No change.
SSD is updated to the latest firmware.
Was this an upgrade, or a new install? On a bunch of forums it appears that when installing Win7 64bit a new, clean install is recommended.
You could try a repair-install before; if you are lucky, a file was corrupted and a repair-install might be able to replace it.