Does heat affect computers?

Answer: Office PC temp range

Of course heat will effect your computer just as it will any electronic device. Operating a computer in an environment that is greater than 80 degrees begins to place it at risk. My experience is that there can be as much as a 20 degree difference between the heat in your computer and the heat in the surrounding room. You do not want to operate the equipment above 100 degrees Fahrenheit for any length of time unless the equipment is specifically designed to withstand higher temperatures. You may experience strange computing phenomenon or reach a failure point when actual operating tempertatures exceed 110 to 120 degrees. This obviously depends greatly on ventilation in and around the computer box. Do not cover or obstruct the intakes to the ventilation fan. If operating in high temperature areas that cannot be cooled, buy equpiment specified for operating at higher temperature ranges.

Added - I live in Australia and my computer is made to deal with most heat, but even in summer i have to take off the side panel and have two large room fans on to keep the core at around 40C in idle, and 50-60C while playing games. If i don't my core EASILY reaches 90C and im left with a computer acting like its huffing on windows millennium haha. In short yea heat can have a HUGE affect on a computer. I recomend using programs like "SpeedFan" to monitor your computers temperiture and control the speed of your fans and cooling systems.