2007 Intel MacBook Pro Pinwheels and Loss of Sound

Question

Hello all,
So, about three weeks my 15" 2007-model Intel MacBook Pro running Snow Leopard began acting very strangely. All at once, after my computer had been on for most of the day, the toolbar item processes like Airport, Sound, Time Machine, etc. all began to display rainbow pinwheels of doom, with about a 10-second return to normality every ten minutes or so. This caused computer actions like playing sound, connecting to internet, opening force-quit, changing volume, etc. to only occur (and all at once) within that 10-second window. Other processes like Safari ran smoothly but very slowly--tabs would reset themselves, Flash refused to load, pages did not change for tens of seconds.  Looking at my activity monitor, I could see that my CPUs were mostly idle, so I think that rules out some kind of malware coming in and gumming up the system. I tried restarting Finder, and then restarting the computer, but neither had any effect, and I also noticed that while shutting down, my computer would display the gray startup screen and a gray loading pinwheel for several minutes between leaving the desktop and powering off.
However, this behavior went away after that night, and so I dismissed it as a minor problem and thought no more of it. In the intervening three weeks (about a week-and-a-half ago), I upgraded my machine to Lion so that I could start an iOS coding project for work--as I upgraded, I also got rid of a Boot Camp Windows partition I'd been carrying around and didn't need anymore.
For the first two weeks, everything went fine, and there were no problems with Lion. However, this pinwheeling/slowdown problem has returned with a vengeance! The same symptoms have appeared, except they are becoming less and less intermittent/more persistent.
I have also been able to verify that my software is completely up to date, and that restarts have no effect on this new appearance of my issue. It seems to come and go as it pleases.
Does anyone have any idea what's going on or how to fix it?

Answer 1

the toolbar item processes like Airport, Sound, Time Machine, etc. all began to display rainbow pinwheels of doom,
For the toolbar issue... it's actually referreed to as the menu bar.
Open the Finder. From the Finder menu bar click Go > Go to Folder
Type this exactly as you see it here:
~/Library/Preferences/com.apple.systemuiserver.plist
Clicik Go
Move the  com.apple.systemuiserver.plist file to the Trash.
Restart your Mac.
If that didn't help, use Lion Recovery  to repair the startup disk if necessary, or reinstall the Mac OS X.