It is a bit vague to tell for sure what's up with your machine, more detail would help. A flashing display is a sign maybe (only maybe) your power supply is on it's last legs.
If you've got the ability, it can bit fixed for £4 or £5 and some soldiering. If not, you can buy an exchange from ebay for about £40.
It could also be the motor brushes, which also can be purchased from ebay for £2 or so.