Yeah I hear you. I have to remind myself not to go to deep and start from the most basic troubleshooting steps first.
Standard WP troubleshooting steps. Deactivate plugins one by one. Switch your theme.
FYI – BPS and BPS Pro have built-in troubleshooting (Security Log, Turn On/Off for every single security feature) so you do not need to deactivate them to do troubleshooting and actually if you deactivate BPS or BPS Pro you no longer have any troubleshooting tools to use. ;)
BPS Pro General Troubleshooting Steps
http://forum.ait-pro.com/forums/topic/read-me-first-pro/#bps-pro-general-troubleshooting
BPS General Troubleshooting Steps
http://forum.ait-pro.com/forums/topic/read-me-first-free/#bps-pro-general-troubleshooting