Ah, to get rid of the sign, you must hit it until it goes away. (Install a full copy mate. Eval copies are time-bombed and pretty much stupid stuff)
That might not be a TB:Eval, even, because the Eval hasn't been around for ''for months''. What I'm suspecting is a normal Windows 8.1 9600 with Preview spp+tokens (aka ''Frankenbuild''). Please note this doesn't change any advice given here: Get rid of that crap and download the real deal!