My daughter's MacBook restarts if the lid is closed and then opened again i.e. it goes to sleep but will not wake normally...

I'm going to try a recommended solution involving disabling Safe Sleep mode which a number of folks have pointed to as a possible culprit. There is an application that will do the job or you can disable in terminal mode. http://www.jinx.de/SmartSleep.html To disable safe sleep, run the two following commands in Terminal: $ sudo pmset -a hibernatemode 0 $ sudo nvram "use-nvramrc?"=false When done, restart your computer. Now go delete the file /private var vm sleepimage" to free up some hard drive space. When you put your computer to sleep it, should happen in under five seconds; my MacBook now goes to sleep in two seconds.