slow GUI

[rgm at htt-consult.com (Robert Moskowitz)]

System:

PIII 500Mhz
128MB memory
20GB drive

Current CentOS 4.2
Gnome GUI

The system runs 'idle' at around 70Mb memory used and 4% cpu usage.

But whenever I go to start a task:

Start Gedit, Services tool, a Terminal window, Firefox

It takes a minute or so.  CPU mayyyypeak at 100% briefly then come 
down.  Memory has yet to exceed 100Mb usage.

Any pointers of where to look to see why it is slow?