Click Start > Type: Event Viewer > Click Event Viewer in results > In Event Viewer click Windows Logs > System and look for any errors around the time of the bluescreen with a Critical or Error !!! exclamation mark
most Likley bad or incorrectly seated RAM. If you just changed out RAM, open PC, re-seat RAM, if it dont work then, remove new Ram, replace with original Ram. Take new RAM back to store, get money back.