Failed Laptop

My mother's HP laptop has failed after 3 years - it will not power-up, or powers up for seconds and the goes dead. She has looked after it very carefully. She has spoken to Comet where it was purchased from and they have been little help and basically said there was nothing they could do and she would have to take them to court under the Sale of Goods act to prove anything. What can she do? She is 78 and not very technically minded and not really in a position to be chasing around independant electrical agents for an independant report. It seems that the Sales of Goods Act puts the onus on the consumer and not the retailer in these situations.
In principal I believe that the laptop should last longer than 3 years and that the fault lies with the laptop.

Any ideas?

Thanks for your response. My mother did visit the Comet store where she got it from and they were not very helpful at all, infact one of the sales people who she spoke to told her that the Sales of Goods Act did not apply in the UK and even after speaking to the Manager she was advised to take it along to get it repaired at her own cost.
They did not suggest an inspection but did provide details of where she could get it repaired - but that she would have to take it herself to do this.
Should she revisit the store and leave it with them to arrange for inspection - and if they decline to do this what should she do.

thanks
Heather