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Thank you for your answers. The problem is, Old_Geezer, that I don't understand some of the specs. They are just numbers to me and when looking up other specs, i.e. on graphic cards, I have no idea which is the more modern or better one.
I agree with you, Cara, I do think it would be better to buy from an established dealer who gives me a 1 yr guarantee.
Alice, I will check that site out. But, while I know what to look for in HDD and a few other things, I am not sure about graphic cards and whether or not in addition to the 1 TB HDD the added 240GB SSD would be necessary. I want to stick around the £400 mark for the computer itself. I can use my old monitor for a short while and my existing keyboard and mouse as well.