About one every few hours, my computer will make 2 loud buzzing noises. My computer had a few problems starting up recently as well, and I'm wondering if it could be the Hard Drive failing. What do you guys think?
More about :computer makes loud buzzing noise hard drive
main suspects are the hard drive or the PSU (specifically the PSU fan).
Test the hard drive with drive maker's diagnostic software which loads from a bootable CD (you cannot test the Windows system drive with Windows-based software). The links are here: http://www.tacktech.com/display.cfm?ttid=287
In the case of the PSU, it can't be tested. Just replace it if it's suspect. Take the opportunity to fit one with a higher wattage rating (output), especially if the existing one is the original factory-fitted unit.