from what ive heard stop error 21 is a nasty error, i installed win 7 ultimate, installed my network and ethernet drivers, no problem there, but i then updated, 87 updates, restarted, and boom there is the bsod, i shutdown and booted up with last know good configuration (forgot the exact wording ) and it booted up fine, should i be fearful of another bsod? and is there any fixes that are out there for this?
From a simple Google search, I've been able to determine that error "x000021" does not in fact exist. Error 0x00000021 does exist, though, but it seems to only apply to Windows 2000 through XP.
If you have another BSOD, copy down the exact error code and search it here.
I have no idea whether or not this issue will re-occur, so the only way to find out is to reboot your machine If it happens again, boot from last known good config again, and search the exact error code.