[iBook] Arrow/Cursor Keeps Freezing

[Fred Stevens K2FRD]

For some months now, my cursor (arrow or I-bar, depending) freezes in 
place during use. It seems to happen maybe once per week, maybe less 
frequently. There doesn't seem to be any consistency except that it 
seems to happen most often when I'm using Firefox or Eudora, probably 
because I use these applications more than any other. When the cursor 
freezes, nothing works and there is nothing I can do (tried all the 
keyboard force quits) except do a forced power off, then power up 
again (takes two or more times before it "takes" and moves on to full 
boot). I'm using a Macally optinet mouse, didn't have to load any 
software to make it work since the necessary software is part of OS X 
(I'm now up to 10.4.5, but it was doing it before I bought Tiger). I 
can't say for certain when it actually started, but it's a nuisance.

Any thoughts on the cause?

Using 14" iBook 900 with 640 mb RAM, 40 gb HD (80 gb Firelite 
firewire external drive used for backup, but this wasn't installed 
until this past Dec); machine purchased in August 2003.

TIA,
Fred

-- 
73 de Fred Stevens K2FRD, VO2FS
http://homepage.mac.com/k2frd/K2FRD.html