How do I restart my Samsung A3 phone after software update failure?

[AC Question]

I tried to upgrade my Samsung Galaxy A3 phone's Android software to Android 5.0 and then after installing up to 100% the device gave an error code. The next download step has been on for the past 3 hours and the phone will not switch off. I have tried pressing the Volume Up+Home+Switch buttons simultaneously and also taking out the sim and SD card but it restarts the software installation and goes back to the same mode. Major challenge is I cant take out the battery to stop the whole process. Anyone experienced anything similar and how did you solve this?