Ok, ANY strange noises or high pitched sounds from a PC is something to be concerned with - it could be trouble. My advice, shut down your tower, unhook everything, take it outside & blow all the dust out of it! you'll need like 3 or 4 cans of air (b/c they freeze up bout 1/2 way, need to rotate) or an air compressor w/ the regulator set no higher than 45psi. Once you have the tower cleaned out, get to a very well lit area, or get a bright flash light, expect the system board, graphics cards, any expansion cards, spin fans with your finger, they should spin freely and continue to spin just a bit after. if fans are tight, replace them. on the system board, look for swollen capacitors (they look like little 1/3" barrels sticking up on the circuit boards see image) - specifically around the heatsink of the CPU - this is where the voltage regular is for the system board. if any of the capacitors are swollen, or oozing black or while slimly looking stuff - be wary. if you have a camera, post a pic or two if you find swollen/oozing or questionable capacitors. if you have none, great! if all your fans are spinning freely, great! Just keep an ear & eye out for issues as such. FYI keeping the inside of the PC clear of dust & debris keeps it running cool. hope this helps, take care!
