Suddenly iPod not synching

Even though the iPod icon shows up on the desktop, my 80-gig video iPod suddenly isn't synching to iTunes. Resetting the iPod isn't working, and the iPod works fine otherwise. I've been having, what I think, memory problems (spinning beachballs, programs taking forever to open, etc.) since I only have 768 DRAM on my G5 20-inch iMac (I have 2 gigs ordered). Could that be the problem? Thanks in advance.