PROBLEM: strange system hang under 2.6.1

[Neil Macvicar <blackmogu _at_ xxxxxxxxxxx>]

When I leave my system just running, doing something or nothing at all, and 
come back to it after a period of time (usually after app. 1 hour or 
greater), as soon as I either use the mouse or keyboard, the system hangs. 
I've tested this over several different periods of time, and the computer 
will run fine after several days, until input on either keyboard or mouse 
occurs. This happens with or without any modules loaded. 

Kernel Version: 2.6.1 (unpatched).
CPU: PII 450MHz

I've attached my config.gz for perusal.

--Neil.

Attachment: config.gz
Description: GNU Zip compressed data