Can ANyone Help - 10.6 Log In Problem

This isn't for me, but a friend. I tend to be the first port of call for computer issues, but I have never really been any good with Macs

The issue he is having is this:

The machine boots OK with the gong sound. The log in screen appears. He enters his username/password then it takes a while, goes to a blue screen then back to log in screen.

He is certain that the user/pass is correct. He has tried it with incorrect info and it advises the username/password incorrect so the machine knows his details are right, just won't allow him in.

Does anyone have any ideas what we might be able to try please.

Hope for some help

Many thanks

Edited by deleted (Tue 25-Oct-11 15:07:16)

Usually wrong credentials just cause the login box to go all wibbley wobbley for a second.

Probably worht eliminating hardware: if the machine has an optical drive, boot from that (hold down C while booting) and see what happens.

Might be worth the time-honoured boot into Safe Mode (hold down the Shift key on boot) (About safe mode)