Nope, reset+power is not hard reset.
Clink on the following link for a step-by-step guide for hard reset. (I hope it is not aginst the rule to put a link in this thread.)
http://t1-reader.ru/en/reference/factory.html
Please note that the hard reset will delete all books and information you have on your PRS-T1.
Hope the hard reset can solve your problem.