Computer's fans spin ridiculously fast upon running L4D2

[Country Steaks]

I've noticed this happening since yesterday. Even when simply browsing the game's main menu, the fans inside my computer will get progressively faster and faster until it sounds like the computer is on the verge of almost exploding. I've checked the processes that I have running in the background and there doesn't appear to be anything in excess to what I normally have running. Any ideas?

Edit: My room is by no means warm and there isn't anything that appears to be obstructing the computer's vents.

[RedPing l Dabook]

Weird,funny too~ hope ur PC dont fly away....sorry i have no idea abt this

[「Izzy」]

Kill any processes you don't need. Steam itself is a heavier process than many others and starting up a game adds to that. If it's only L4D2/games that does/do this then you might want to buy an external fan to make sure your computer doesn't start overheating.

[Kitsune]

You might want to check inside the computer, the CPU might be overheating. If this only happens with L4D2, though(no other games give you this issue, including ones that should be more intensive), I'd suggest submitting a ticket to Support with your PC specs.