hi, i just installed a second sata hd (western digital caviar se16 - 500 gb), and afterwards a low humming noise (that goes high from low constantly, regardless of whether computer's thinking or not) started to come from my computer. I opened it up, and the sound isn't actually coming from the HD, but rather somewhere near the PSU. I uninstalled the second HD, and the noise stopped. So i'm wondering whether my PSU is not powerful enough to operate 2 HDs? I know from the reviews WD Se16 500gb is supposed to be quiet... my powersupply is Thermal Cooler ATX 12V, with max 350W (+12V, 10A; +5V, 14A; +3V, 14A). My first sata HD holds 160 gb (seagate barracuda 7200). other stats : motherboard : gigabyte tech co. 945PL-S3, bus clock 200 megahertz processor : 3 gigahertz intel pentium D, 16 kilobyte primary memory cache, 1024 kilobyte secondary memory cache graphic card : radeon x300 series if someone could please advise me, i'd much appreciate it.