Hi @keishna
Try a power refresh and check if that resolves the problem.
[https://www.manualslib.com/manual/544019/Samsung-Gt-S5302.html?page=13#manual|Remove the back cover] from the phone and then [https://www.manualslib.com/manual/544019/Samsung-Gt-S5302.html?page=14#manual|remove the battery]
Press and hold the phone's Power On button for a ''full 30 seconds'' and then release it.
Reinsert the battery and replace the back cover and check if your phone now turns on OK.