BSOD before login screen

Hello!

I'm using Windows 7 64 bits.

I've never had any problems on my computer until today.
I installed the game Civilization 4, which isn't supposed to run perfectly on Windows 7...
I runned it, and it shut down my whole computer.
I tried it 3 or 4 times, then it became serious.
I can boot on safe mode, but on the "normal" mode it crashes in a BSOD flash (like, 1 second) just before the login screen, then shut down the whole computer.
I tried system recovery many times, but it didn't fixed the problem.

Help me please :'(

I found what was written in this BSOD . Here it is :

STOP:c000021a {Fatal System Error}
The initial session process or system process terminated unexpectedly with a status of 0x00000000 (0xc0000001 0x00100510)
The system has been shut down.

Collecting date for crash dump...
Initializing disk for crash dump...
Beginning dump of physical memory.
Dumping physical memory to disk : 100
Physicial memory dump complete

And here is what Windows tell me when I reboot on safe mode after that :

BCCode: c000021a
BCP1: FFFFF8A0018621F0
BCP2: 0000000000000000
BCP3: FFFFFFFFC0000001
BCP4: 0000000000100510
OS Version: 6_1_7600
Service Pack: 0_0
Product: 256_1