Popping noises over headphones/speakers at F/B panel !!! HELP!!!

Hello. I have these specs
-Asus M5A78L-M/USB3 - > Out of Stock ;/
-AMD Phenom II X4 955 3.2GHz 8MB cache Black Edition - > Out of Stock ;/
-ALPINE 700W PSU - > Alpine 700W Silent PSU with 120mm Red Silent Fan 24+4 Pin Intel v2.03 Enhanced +12V - Scan.co.uk
-Corsair RAM 2x2GB / 4GB 1600MHz 1.65v Dual Modules - > Corsair Memory XMS3 4GB DDR3 1600 MHz CAS 9 XMP Dual Channel Desktop - CMX4GX3M1A1600C9 - Scan.co.uk
-Gainward nVidia GTX 550Ti Golden Sample / GS - > Gainward GeForce GTX 550 Ti 1024MB Golden Sample NVIDIA Graphics Card - 426018336-2043 - Scan.co.uk
-Pioneer DVD - > PIONEER DVR-S19LBK DVD Writer, SATA, Labelflash, Retail - Scan.co.uk
-Samsung Spinpoint F3 HD103SJ - > Review - Samsung Spinpoint F3 1TB Review | bit-tech.net "same price as when I purchased it"
-Heatsink - > Coolermaster Vortex Plus CPU Cooler - RR-VTPS-28PK-R1 - Scan.co.uk
-Case - > Xclio / Meridian Technology Godspeed Two Full Black Mid Tower Computer Case - Scan.co.uk..
From the very beginning I had sound delay problems "note that I haven't got any speakers, been on my headphones" but I were on XP OS... then I went on W7 and delay stopped...perfect...great...wohooo. Eventually I bought speakers which are Logitech X-530 5.1 and I started to hear some kind of popping/clicking noises constantly "it's the same noise when you power ON your speaker into a power socket" and now it's even more of those weir sounds... Went with my 1.)motherboard with 2.)CPU and 3.)RAM modules on it only to the store where I bought them from.... told me that it might be 'cause of thermal paste which somehow got onto CPU's socket and CPU's ping but not 100% sure so I had to leave my motherboard to be cleaned up and got told to wait for 28 days..Couldn't wait for that long so I bought another exactly the same motherboard.. Well I got back home cleaned up the CPU to a perfect / mint condition.. joined everything together STARTED , well what do you know..SAME PROBLEM...then I tried my friend's same CPU as mine's ...... SAME PROBLEM "AGAIN"...Then I tried different RAM modules...SAME """"AGAIN"""""....So I don't have a clue what the hell is happening ? Tried re-arranging parts with my friend's ones and no positive results. Please help / suggest something I could do...
Forgot to mention, when I bought new motherboard I've also bought ASUS Xonar 5.2 sound card just in-case and same noises goes through it as well ;/

weird, I'd try making sure all your cable connectors in the computer have nice firm connections. In the good old days, I'd even suggest putting an old radio next to the PC to see if you get any popping from that, suggesting that indeed there's a loose connection in there somewhere. My only suggestion other than checking all the connectors is to try a different PSU

Sounds like you've tried a lot of things. Are there any parts that were common to every combination you tried? like the same monitor on every PC, for example? If one thing was was the same on every combination, maybe swap that out. Such as the PSU as suggested by jpdavidson.