Game Uninstalls Itself, Repeatedly crashes computer

So my Intruder game was working perfectly fine until rather recently I've been experiencing the game just full-on causing my entire computer to blackout and do a crude restart. I've tried multiple options such as making it to where my computer cannot restart during a system failure, reducing the amount of power it puts into programs, reinstalling both the game and the antivirus, etc. I'm unsure what's causing it but it's making the game downright unplayable for me. On top of this, there is another problem where I log onto my steam only to see that the game Intruder is not even installed in my library when I clearly had it installed no less than a day ago.