Servers crash and pc crashes?

Info on the system first:
Xeon E3 1270 v3 3,5 Ghz
SSD and HDD
16 GB ECC ram

I have a server pc with my friend, and we have in total 4 servers on that pc.
His servers are a part of a lobby server, so that means no more than 1 gb ram. My server tho is a "main" server and uses 6 GB ram approximately.

Here are the crash reports for his server (My server just stopped at a player message... So no info there):
- http://pastebin.com/1tvgASiN
- http://pastebin.com/9m0bvYYw
-...

Servers crash and pc crashes?