Scrolling mouse or keyboard causing static/distortion through speakers

Hi,
I'm a new poster. I need some ideas/help. For the last 2 years, I have had the issue below however it has not been an "issue" for me and I have just dealt with it. A few days ago though I upgraded to a better PC sound system and now I need to try to fix this thing.

What is happening is that ANY scrolling (on my mouse scroll or my keyboard scroller) or ANY sudden quick mouse movements while in Internet Explorer while listening to music via the internet (ie on youtube) causes a high pitched distorted like SCREETCHING/STATIC through my speakers. The odd thing is that if I SCROLL OR MOVE THE MOUSE SUDDENLY for a bit longer once the issue happens on the internet while music listening it will "fix itself". The screetching will go away. Scrolling some more though after it fixes itself will bring back the problem---annoying. Another oddity is that the issue not only happens while I am listening to sound while on the net (music) and scrolling around BUT ALSO NOW It is also happening when I'm NOT on the net and say in Windows Media Player and I scroll through my songs or move my mouse any which way quickly (on keyboard scroll too!) then the static distortion happens.

I have googled the subject. TONS of possibilities exist---dating back as early as the year 2000 that I could find---so that was like even in the stone ages of PC (ie. its not some Vista issue or some specific Soundcard issue or something)! I have tried all I can and am at my wits end. I have had the PC (HP Pavillion a6250t) for about 3 years. As I said the issue has been in the last 2 but I have dealt with it. I seem to remember them occuring when I put a new laser mouse and new Logitech keyboard in a few years ago, but as you will see below both have been changed back to "stock".

Here is what I am running:
Vista 32 bit w/ service pack 2
2GH Pentium Dual E2180
SB X-Fi Xtreme audio Sound Card
NVidia GeForce 8300 GS video card
1 GB Ram
IE 8 (upgraded to 9 today to try to fix it)

Here is what I have done:
Updated Windows Vista
Updated my sound card drivers (they did indeed update)
Ripped out ALL USB devices (newer mouse, newer keyboard, printer) and changed back to stock PS2 mouse and PS2 keyboard that came with the PC in an attempt to eliminate IRQ conflicts)
Updated to IE9 (problem is really bad when I'm on the internet scrolling or "mousing" during music)
Turned off mic and all inputs unused on sound card (muted so no feedback can occur)
Switched from analog out to digital out on SB soundcard (digital now runs to external preamp to be decoded--problem stayed the same)
Uninstalled all old USB keyboard and mouse software (now running ps2 all the way)
Uninstalled iTouch and Mouseware from Logitech (been known to cause my exact issue)

I mean does anyone have an idea of what to try next? From what I have read on the subject; there is a possibility of some RFI interference causing this. The sound card is indeed right on top of the video card in my PC. There are 2 slots above it free I can plop the sound card into if I have to. Its just odd that when the PC was new for the 1st year NO ISSUE LIKE THIS was there. Then it appeared. So I'm just not sure what to try next!! Any advice would be appreciated! Thanks!