Medion MDPNA 100 screen switches off

This is driving me nuts. Need help bad.
I've spent every available minute during the last two weeks trying to get Tom Tom to run on my MDPNA 100.
I have finally achieved it (Woooo Hoooo!) and now the damn screen switches off each time I tap it. It switches back on if I tap it again or if I press the SATNAV button.
Please, Please, Please there must be some one who knows the answer.
Please help before I revert to an AA map book and my old PSION in desperation.

Thanks,
3DDevil

have you checked power setting m8 mine did it because it had turn off after 1 min mught be worht a check

ps how the hell did you get tom tom to work my pna100 can never find a bloody satallite