If Adobe Acrobat loads exceptionally slowly, including a spinning wheel and 'Not Responding', a single security setting* change could solve your speed woes. So before you uninstall and reinstall Acrobat, follow these steps: -

1. Open Acrobat (slowly)
2. On the menu, click 'Edit' and then 'Preferences.'
3. Select the 'Security (Enhanced)' menu item
4. Deselect 'Enable Protected Mode at startup (Preview)

Disable Adobe Acrobat Protected Mode at at startup to resolve slow load

5. Click 'yes' on the 'Disabling Protected Mode...' dialogue
6. Manually restart Acrobat

This setting change should resolve the Acrobat slow load and unresponsive issue.

What does Adobe Acrobat Protected Mode do?

Adobe Reader runs in protected mode default mode to provide an additional layer of security by confining files to the 'sandbox'. The protected sandbox environment prohibits malicious PDF documents from launching arbitrary executable files or writing to system directories or the Windows Registry. *If you intend to open a range of PDF documents from untrusted or potentially malicious sources, you may prefer to keep the  Protected Mode setting and put up with the slow Acrobat load.