Samsung galaxy ace wont turn on!

Welcome to Android Forums gunners

first off i must ask as i am not entirely familiar with the samsung galaxy ace

you need to boot into recovery (stock recovery as i am sure you are not rooted) and you need to see if wiping data and or cache will help.

doing these tasks may work and bring your phone back, however once you wipe data you will lose all text messages, and app data, your pictures and videos and music will be fine.
saved game data will be gone, as well as call log, and text messages

i have a feeling you need to hold a volume up or down button along with the power button to enter recovery.

or you can leave your phone plugged in to charge, and let it sit there for 30 minutes then try again.
i would recommend letting it charge first as that may be an issue.

 

I hope your time here will be useful. Welcome aboard.