Help! Constantly crashing mac.

[3littlefrogs]

Distraught teenager is desperately trying to back up files before the mac dies, but it keeps crashing before the back up is complete.

Before I try to book a session in London, can anyone recommend a reliable trustworthy company that might come to us? It is going to be so difficult to organise time to do this.

I have spent a couple of hours in the local computer shop, and spent £60 on an external hard drive, but we have been trying to back up files for the last 3 hours and can't do it because the lap top keeps crashing.

My nerves are in shreds and the homework hasn't been done...

I would really appreciate some advice.

(The screen goes green and black and alarm sounds).
TIA

Anybody?

I have just googled 'my mac keeps crashing' and most results indicate that a recent download can cause the problem. Have you any recent downloads you can remove? Sorry not much help

My wonderfully competent Ds has managed to copy everything onto another hard drive and booked me an appointment with the apple store.

Thank you for your reply though. I appreciate it. I was panicking last night, but things look better today.