My computer does not like winter. Below 17 ? 18 degrees the computer will not start, despite repeated attempts. After heating the room to 20 degrees the computer starts immediately without problem. Is this normal, or does it indicate a hardware problem? The computer is running Windows XP.

This is not normal, as the computer should be able to start and operate at most room temperatures (excluding very extreme temperatures). The behaviour being exhibited by your computer indicates a potential thermal management problem with the computer hardware, as it does not respond well to differentials in the temperature. I strongly suggest that you have the computer checked at a computer store to determine why this is occurring, and whether it can be fixed, since this could potentially lead to greater problems in the future, as thermal problems can lead to other issues such as potential computer overheating.