Why is my samsung galaxy tab 4 8.0 not working?

I downloaded a applocker app and decided to lock all 73 of my apps and then I tried going online and when i did it asked me for a lock code, which i got right, and so i serched facebook and clicked the link but then it asked me for another lock code. So I did my lock code again but it just stayed on the code like it didnt say i got it wrong or right it just wont let me do anything! Not go on any apps, turn off the tabelet, it wont accept the code i put in because when i do it just stays there. I dont know what to do to fix it, can you help me?