Trumpy, rumbling from the fan in the PSU probably means dry bearings, especially if it deteriorates to rumble at odd moments then those moments become longer.. and so forth. It's possible to switch out the fan in the PSU, but may not be worth your time as PSUs are cheap. I wouldn't advise most people to go poking around in a power supply, but then most people don't do linework [Linked Image].
A temporary fix may be this .