High pitch noise from speakers w/ realtek problems

Hi all, I am having some issues with my custom PC. I built it last year around August. It was working like a dream until recently. I traveled out to California for school, and had it shipped via UPS to me from Chicago in November. Since then i have only had problems. To begin, when i opened the packaging, i also opened the side panel of my chassis to make sure everything was in tact, and found only one thing out of place. The Main 24 prong power connector from the PSU to the Motherboard was disconnected. This was crazy because there is no amount of shaking and jumbling around that would make that cord unclip and fall out of the socket. Anyway i thought that was the problem. Because i plugged it in, then tried booting my computer up and got no signal to the monitor. However the Motherboard LED light worked. So i ran tests and diagnostics until i eventually figured the motherboard must be dead. *By the way in the process of testing, i also manually reset the bios with the three prongs near the USB socket.*

So then i decided to RMA the motherboard. As i was taking my PC apart, i pulled the motherboard out, unscrewed the CPU fan from the board and noticed the CPU was stuck to the bottom of the CPU fan (the thermal paste). So i placed it back in, put the PC back together, then booted it up and it started. The first screen that popped up was some kind of Bios recovery screen? it had to options, one to restore to defaults and the other to do something else. It was silly of me, but because i was so excited, i simply chose the restore to default option. It then booted to windows (windows 7 64 bit ultimate). Everything seemed fine, and everything WAS fine except the sound.

For some reason, when i plug my speakers into the back, all i get is a high pitched noise from the speakers. I can lower and raise the volume of it, but it sounds like a sketchy broken high pitch white noise. Its not the speakers, i tested them on the PS3 and they work fine. This irritating noise is true for all 8 line in, speaker and mic outlets on my computer. To add to this, my realtek audio manager is flipping out. Every time i boot to desktop, realtek pops up over and over again saying i plugged something in a jack, then it wants me to choose what it is (speakers, mic, line in, etc) but then it will say i unplugged it and go back and forth. Obviously nothing is touching the jacks. I have tried updating the drivers, and a system restore. The device manager says nothing is wrong. So i think maybe its my motherboard? Any help would be greatly appreciated. I apologize for the long question. Thank you.