If you're seeing this issue in most cases its a graphics card issue

1 - Make sure windows is fully updated until 'No New Important Updates are Found' (this may require multiple restarts and multiple 'check for updates'), including Internet Explorer (even if you use a different web browser).
2 - Update your graphics drivers - FAQ - Hold'em Manager (HM1) Poker Tracking Software :: How To Update Your Graphics Card Driver
3 - Enable desktop composition - Enable or Disable Desktop Composition ~ Windows 7 Support

The following solutions have also proved to be helpful in resolving this although these are usually isolated issues
1 - Set desktop to an aero theme:
- W7 - How To Enable Window Transparency (Aero) On Windows 7 - Windows - Windows 7
- W8 - How To Enable Aero Glass-Style Transparency in Windows 8
2 - Update Logitech Setpoint - http://www.logitech.com/en-us/584/3131

In HUD Settings - General Settings - Advanced Settings - change the z-ordering setting.

Sometimes the .net framework installation can become corrupt. This can cause several problems including freezes on startup, registration issues, crashes and more. The following FAQ walks you through safely uninstalling .net framework and reinstalling it again - Hold'Em Manager 2 FAQs - Poker Software :: Holdem Manager .NET Cleanup and update Instructions

If you continue to have problems, please duplicate the issue and send us log files with a detailed description of what you were doing and what problems you were experiencing:
- Open Windows Event Viewer's (Control Panel > System & Security > Administrative Tools or Start > Search > 'Event Viewer') > Windows Logs > Applications.
- Check for any errors and send the information (Save All Events As...).
- Please send a log file as well - Hold'Em Manager 2 FAQs - Poker Software :: How Do I Send a Log File to Holdem Manager Support?

When sending any files please zip them (right-click > send to > compressed folder) before attaching them to an email. If the attachment is larger than 10MB please upload them to a file hosting site like dropbox, then right-click > 'copy public link' and paste the download link directly into the support ticket email. If you have any problems with dropbox try using filedropper.com