[ex is moor]

Hiya

My G4 867MHz is getting grumpy in it's old age. It has recently started making a bizarre chirping/grunting sound (no, really!). While this is happening it locks up, often displaying the spinning wheel of death. It sounds a bit like the DVD drive is tring to read a disc, although there's nothing in there. I have tried to locate the source of the sound - I think it's coming from the back of the computer, not the disc drive.

I have tried various maintenance procedures - verify and repair permissions on the startup and other disks, reset NVRAM, and do hardware checks.

Although it passed all the seperate tests (airport card / logic board / mass storage / memory / modem / video RAM)
the hardware check came up with the following code:

Error code post/16/2048

From googling the error code, it looks like it might be a RAM problem, but I dunno what to do next. I did try removing one bit of RAM, but the G4 made lots of scary beeping noises and refused to reboot. Any suggestions?

Thanks