Which version of Lightroom are you using and what is your computer's OS?
Does the app freezes while using any particular tool or using any specific function? Would you mind deselecting the option "Use Graphics Processor" located in Lightroom's Preferences > Performance menu, then relaunch the app and see if it helps?
Also, even if you've reinstalled the app, a preference file will survive a Lightroom uninstall/reinstall. Sometimes weird behavior is corrected/cured by resetting the preferences.
1. Close Lightroom.
2. Hold down [Alt/Opt]+[Shift] while restarting Lightroom.
3. Overwrite the Preferences when prompted by the dialog.