This is the standard Windows 'blue screen of death'. Common problem caused by most Windows applications / programs (I'm not a fan of microsoft!). If it does this using word or excel then just go for the restart. Once you're back in, go back to the application and open the file you were using at the time of the crash. My experience is that the file will re-open with the word 'recovered' after the file name in the bar at the top of the page. Save it immediately!! Too many blue screens of death mean that you could be in for a rebuild. I hope not!!