Drupal crash issue

hi friends,
From last few days most probably since I upgraded to drupal 7.36 I am facing an issue which is " Drupal crashes suddenly, the toolbar goes away and all I can see is the website I am developing, no admin blocks, sidebars disappear too. And I have to do all the installation again Drupal Dev + Drupal, which is very annoying and wasting time".

Is it modules, database or admin theme is crashed?
I want to know is it any other better local host stack (bitnami) which run drupal stably or any other suggestions please!

regards