My situation:
When my heating has been on and the rooms are warm, I switch my PC on and it doesn't make a loud rattling sound.
When my heating has been off, the rooms are cold. I switch my PC on and the loud whirring sound is there. I have to leave it running for a few minutes before shutting it down completely. When I reboot it back up, the whirring sound goes, like something inside the tower has warmed up enough.
My question:
What could possibly be cold enough to start whirring? It only ever happens when the room is really cold.
Any info much appreciated