Currently Being ModeratedNov 10, 2012 6:10 AM (in response to murjek)
That's a kernel panic which is usually, but not always, caused by hardware, with memory the leading cause (assuming there are no external devices attached). See this Apple note on troubleshooting it.
Currently Being ModeratedNov 11, 2012 2:42 PM (in response to murjek)
Restarting the MacBook with the Option (Alt)-key pressed I came to Mac OS X Utilities where I could use the options available to restore the Macintosh HD from my external MacBackup disk used for Time Machine. Before that I had checked that the RAMs didn't seem to be any problem with and also the HD on the computer seemed to be OK.
So it seems that it was a software problem and I was able to restart the computer and it now seems to work OK.