Hello Glenab
The information you gave about the issue is too short to diagnose the cause of the problem. Can you please provide more details such as which operating system are you using, what was the last thing you did after which you started facing this error, from where did you download the recovery disc, is or was there any error code displayed on the scree, etc.?
As for now, you can try the suggestions
given here to see if the problem is solved.
Feel free to come back with more details to help us give you the accurate solution for the problem.
Good Luck!!