Nokia 6600i screen timeout

I have just got the Nokia 6600i slide phone.

Unfortunately there is a power saving feature of some-sort that is a little
too good for its own good. It keeps turning the screen off after about 5
seconds. If I'm reading a text or something, I just don;'t have time. I'm
trying to find out how to change it,but obviously its really hard as soon as
I get into the menu and start reading, the screen has gone blank.

Anyone with any ideas please? I'm depserate

I have tried Menu>settings>display> and have turned off screen saver, power
saver, sleep mode etc...

Thanks

Andy.