System slowing down to a stall.

[Divided By 0]

Hi,

The last few days I've been plagued by this problem. As the systems 
works on, slowly but surely it begins to slow down. MP3 songs stop every 
now and then and then proceed (progressively more frequently), mouse 
cursor becomes unresponsive or slow, scrolling text (like from 
Knewsticker) moves sluggishly etc.
At first I just rebooted but the problem reappeared almost immediately. 
The next time I did a *ps aux*  to see what process is eating everything 
up, but other than a dvd ripping process, everything else was eating 
miniscule amounts. Then I started killing anything that looked 
suspicious after closing all my active tasks.
My first suspect was a process that kept doing some kind of piping 
search on my system (I don't remember the exact name of the programs 
used, but I remember it piping the results to awk.). Since I'm kind of a 
newbie, I feared for intrusion even though I'm behind a NAT router and 
the linux firewall so I killed the process and my modem. It didn't help, 
the system was still slow.
I'm using azureus in linux as my bittorrent prog of choice and I noticed 
that even though I had shut it down before, its process was still alive. 
I killed it and the system appeared to become normal again. However 
until now, I've been using Azureus without a problem and it seems 
strange to me that it started slowing everything down just like that.
I then restarted azureus and went AFK for a day or so. After coming back 
I find my system stalled in the Screensaver (which meant not long after 
me going AFK since I also have power saving mode on). Only thing I could 
do at that point was reboot to windoze.

So is there anything that can show me what's eating my system up? 
Anything syspicious I could check?

For the record I'm using FC3 with all the latest updates, I'm siting 
behind an ADSL connection and I've been using FC3 for a while now. 
However I just don't know where to look to find the latest source of my 
troubles :(

Any help appreciated.