If you use olly you can find script here that will help you find OEP..
ExeCryptor v1.5x - find target's OEP (by loveboom)
http://ollyscript.apsvans.com/ its not for last version which is 2.0 but i think it will help you if you check it
but here is solution anyway.. :
if you know REAL OEP just dump from there set it with a PEeditor ... fix IAT ...same process for all packers/protectors, when you reach real OEP exe/.dll will be fully decrypted for most cases ..
bye NeO