I bought a computer to study, me knowing nothing a...

I bought a computer to study, me knowing nothing about computers I trusted the seller who advised me the MOST EXPENSIVE computer, moreover he encouraged me to take the guaranteed confo excellence to be sure not to have a problem afterwards. When I got home I noticed that the computer was very slow and that for more than a year now. The garentis offers me, if the computer is defective, to make me a card having the value of the computer to buy me another. Whenever I send the computer to the technician, he tells me that everything is fine when it is practically UNUSABLE and we cannot give the card credit. Beware of warranties and PCs at conforama.