Random alt-tabing when gaming

[SNITCH]

Been having this issue for a while and it's very very annoying. So when I'm gaming (mostly source engine games) I get alt-tabbed or booted out to desktop, this is especially annoying when playing CS:GO and I'm really getting into the game. When i play i turn skype to Do not disturb so skype is not the issue, and when I get booted to desktop there are no programs asking for my attention I've ran multiple scan on MalwareBytes and Avast!. I really don't know what is causing this and this is really annoying me so can you guys please give me suggestions to fix this returning issue?

 

[basroil]

First thing to do is make sure it's not user error, i.e.:
1) You aren't pressing the Windows key or Alt+Tab
2) Making sure sticky keys is disabled
3) Making sure you have only one non-conversion (IME) language installed
4) Opening the game and not inputting anything (checks to make sure it's not just a game bug)

Once you rule those out, give us a list of everything in your details tab for the task manager. Something there is taking focus.