Hi.
A friend of mine told me the other day, that his computer (few months old) restarts automatically. It is not probably the overheating problem, because otherwise it just shuts down, but it restarts. Do you recon it can be a spyware case?
On a brand new system it would more likely be one of two other things like a faulty power supply or a need for a bios update. If the system is running a dual core cpu a need to update the bios would be one thing to look at there. A weak cap in the supply would be another item to consider if the bios chip itself isn't seeing a problem.
If the supply sees the power level drop when the supply itself warms up that could easily the sudden restarts. That would be an unstable supply there needing replacement. Bad caps on the board itself or a flaky bios would see this type of problem. If the system has an extended service warranty the best thing to do would be to have your friend bring it back to the dealer. On a custom build you would have to isolate the hardware with the fault and have that replaced by the manufacturer.