If you can't get it to boot into android you don't have many options. You could try getting into recover (which requires shutting it down then booting it up while pressing some combination of buttons - varies between manufacturers, but volume up, volume down, or one of those plus power would be likely things to try). Once there you should try wiping the cache then rebooting. If that doesn't help then a factory reset - that will erase all installed apps and data, but it sounds like you've done that already in which case you've nothing to lose.
If that doesn't do it then either reinstalling the software from scratch (which we'd need to know the exact model to be able to advise on - I personally don't know Proscan devices at all) or sending it in for repair would be the only options really.