2 months PC BSOD

[giavou]

my system is:
AMD FX6100
MSI 990 MOBO
KINGSTON UV400 240GB
MSI GTX960
WD CAVIAR BLUE 1TB x2
aand psu DEER 600W

after 2 months i have a bsod when i play The Crew.. and then in 3 days i have 4 mores.. without do nothing.. when i do reboot this messege appear "BOOTMGR missing''.. i boot in BIOS and the ssd is disappear.. i unpluged and plug again and its there.. what iw happen.. may the psu cause the bsod ..?
SORY FOR THE BAD ENGLISH

 

[Aeacus]

Before trying to fix your system, switch out your PSU as soon as possibe before it fries your entire system!
Reason for that is that all DEER PSUs are Tier five PSUs.

PSU tier list: http://www.tomshardware.co.uk/forum/id-2547993/psu-tier...

I suggest getting a Tier two PSU, e.g. Seasonic S12II-520.
specs: https://seasonic.com/product/s12ii-520/
pcpp: http://pcpartpicker.com/product/fZyFf7/seasonic-power-supply-s12ii520bronze

As far as BOOTMRG missing error goes, here's a guide to fix it: http://pcsupport.about.com/od/findbyerrormessage/a/bootmgr-is-missing.htm