If you did a "Hard Reset" of the tablet, well many things may not work the same, and your personal stuff should be gone, as a "Hard Reset" Clears it and then re-installs the original OS.
Is it things you had before, that you don't have or don't work now, that are the problem? Or is it items that came with the phone?
Your best bet, before trying to run or install old stuff, or use anything you had on an external SD card (which shouldn't be erased) is to first update all the stuff on the phone. When reset all updates are removed too. Once updated, then try installing all the things you had before.
But be careful. If it was an app that caused your problem, and need for a reset, then I would not reinstall that app.