I'd imagine if Windows 7 was a "Battery destroyer" after all this time people would have posted on it.
It's totally unfortunate in the instances you had -- both HDD and battery -- I'd check the warranty if I were you -- sometimes there's a 2 year warranty on things like batteries.
I don't know where you bought the laptop -- but if you know some "Scrobbity" lawyers and you paid for it with a Credit Card (not a debit card) you might get away with a claim under an equivalent of the UK "Section 25" of the CCA (Consumer credit Act). (Sometimes -- although usually rarely Lawyers DO have their uses !!). Consumer Credit Act and Your Consumer Rights | Consumer Information
(Read 2nd paragraph).
The UK doesn't have the greatest consumers credit protection -- those AWFUL pay day loan companies such as WONGA etc with 3000 % interest are allowed to operate the UK in spite of being banned elsewhere in Europe - but the Consumer Credit Act tends to be fairly similar throughout the EU / EEA as well so if you paid with a credit card the "Section 25" equivalent" might get you a decent refund.