My fascinate wont turn on, even when it was charged all night

If it has been on the charge all night then it should be fully charged regardless of any problem that has occured.

The first thing to do would be to try to shut the phone down like you normally would. If you can't do that then go to step two. Remove the battery wait 15 seconds then reinstall the battery and try to start the phone.

Installing a typical app with the phone plugged in shouldn't have caused a problem nor should have installing an app and ignoring the phone for a few hours. It's possible you installed a badly written app and it caused the issue. If the above mentioned procedure doesn't fix the problem post here again and I or someone else will try to help.