[iBook] memory problems with G4 ibook

[Dennis Reeder]

14" G4 1ghz ibook.  This ibook came with 128mb soldered on the board  
and one open slot. Installed a 1 gig memory stick in the open  
available slot.  Memory came from Omni Technologies.  Purchased about  
3 months ago.  Was running Panther when the new memory was  
installed.  Worked perfectly.   Installed Tiger.  Has continued to  
work perfectly.

ibook is now running 10.4.2 with all of the current available  
updates.  Within the last couple of days it seems to be running  
slowly - seeing the spinning beach ball way too often.  Opened About  
This Mac and was surprised to see that I only had 640 mb of ram.  Hmm.
Pulled ram out and reinstalled it.  Started up machine and About This  
Mac says 1.128 Gig of ram.  Ibook runs for about 4 minutes and then  
freezes.  Froze while running Firefox.  Only other app open was  
Mail.   So I restart.   Open About This Mac and I am back down to 640  
mb of ram.

What gives?

Warranty has expired (it had expired when I bought it "new" from  
MicroCenter) and there is no AppleCare.  Long story, not worth  
retelling.