Computer locking up after several days' uptime

[Dotan Cohen]

A new Ubuntu user has 8.04 installed on an LG laptop. I do not have
the machine nearby to check what the specific hardware is, but it is a
fairly modern unit.

He is reporting that after three days' uptime the computer locks up.
He did not have this problem in Windows. I asked if he could leave the
machine running without programs for a few days' time to see if it is
the OS or an application, but this is a work machine so he cannot do
that.

Where can I begin troubleshooting? It may actually be a while before I
get to the machine physically, so whatever I can ask over the phone or
via SSH would help. Thanks!

-- 
Dotan Cohen

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