Why is strange noise coming from my computer?
Some noises from your computer are normal. Strange noises, the kind that are new to you, not normally heard, may be cause for alarm. You will have to try to determine where the noise is coming from in order to know how to address it. One way to do this is to take the side panel off the case, cup your hand around your ear, or hold a cardboard paper-towel tube to your ear, and listen to the various components in your system.
Is you Hard drive making a click-clacking noise?
If you suspect the hard drive is the noise-maker, shut down the PC, disconnect the drive’s power cable, then turn the computer back on and listen again. If you are sure the hard drive is the source, test it with a diagnostic made by the manufacturer of your hard drive. You may download such a utility here: Utilities & Fixes
Is the sound coming from a fan?
If you are concerned about an unusual fan noise, use the free SpeedFan tool to see if a cooling fan attached to the motherboard is spinning too slowly. Some components may be damaged if not properly cooled, and a new fan costs far less than a new CPU or GPU.
Is the system speaker beeping?
While the normal beep before boot-up, a single short tone, is a universal “all tests passed” signal, other beep codes may point to RAM, video, or other component issues. The beep codes vary by BIOS and motherboard manufacturer. In addition, some motherboards contain diagnostic LEDs that can give you a more detailed report about what’s wrong. You’ll have to refer to your motherboard manual to determine the meaning of a specific POST codes. If you can’t find the information there, check out BIOS Central for an encyclopedic listing of beep codes and their meanings, organized by BIOS manufacturer.