Comet PCs only good for one year?

Got a letter from Comet today which said, in summary, 'Our PCs will only last a year - if they fail after that you will have to pay to fix them. How about paying us another £60 a year for a warranty?'...Cheeky Beggars!

Now correct me if I'm wrong, but my understanding of the Sale of Goods Act is that goods must be (& I quote the act here) 'fit for all the purposes for which goods of the kind in question are commonly supplied'.

Now if I'm paying £600 for a PC, one of its main purposes should be to continue working as a PC for at least 3 years.

I think if said PC does fail, I shall be testing my theory with legal action!