It is an 0xc000021a, which occurs when either Winlogon.exe or Csrss.exe fails. When the Windows kernel detects that either of these processes has stopped, it stops the system.
This error may have several causes, they are listed hereunder:
1. Mismatched system files have been installed.
2. A Service Pack/or update installation has failed.
3. A backup program that is used to restore a hard disk did not correctly restore files that may have been in use.
4. An incompatible third-party program has been installed.
In your case the error cited Csrss.exe as the failing process.
I am assuming you've been able to boot the system normally again. So watch out for the above suspected issues, and see whether you can come up with something tangible, in case you get more BSODs please do post minidumps for analysis. Regards