Carolyn, ProScan PLT7650G stuck on boot screen, may have to do a factory reset. You may loose all saved content when reset is done, so hopefully it has been backed up. This instruction was found in a forum below. I believe your tablet may have a small hole in the case which will allow you to access the reset button with a straightened paper clip.
Insert paper clip, push in gently hold a few seconds till screen reboots, tablet should now be reset.
Hope this helps, Good luck.
http://www.hard-reset.com/proscan-plt722-hard-reset.html