Screen going blank

[steve1]

I run tom tom software on an hp ipaq pocket pc 4100, everything has been fine, apart from having to do a soft reset on a regular basis, but I've been told that this is normal, only today, the screen has started to turn itself off after a while, turn it back on and it goes straight back to the map, anyone got any ideas, or is it a job for the warranty department.

Cheers, steve.