Sounds of the hard drive stopping and starting are a sign the something is wrong. As it is a new machine, contact the supplier and insist that something is done about it.
I'm not sure of the details of your rights on this but, the law is on your side and it is incumbent on the supplier to sort you out.
How did you pay for this machine? If by credit card, tell your card company about it just in case you get any flak from the supplier.