Not 240... I think the switch says 230.
Could be 220, 230, or 240. As far as PC power supplies are concerned, it's all the same (they are only
nominal voltages anyway -- in practice your "240" volt supply can vary up or down by as much as 15 volts at different times of the day).
Today I did a registry clean. Not sure if that's going to help, but someone suggested it... and it's the first time I've heard of such a thing.
The Windows registry keeps track of all sorts of things on the system, and it can certainly cause problems if something isn't quite right in there. You can actually view the registry by hand by dropping to a DOS prompt (or in XP etc. click on Start -> Run) then entering the command "regedit". (Don't edit anything in there unless you know exactly what you are doing!)
One of the problems with Windows is that it collects so much dross over time that the registry and other system files can easily end up in a mess. Even if you exercise very strict control about what you install and run, you'll find that after a couple of years or more the system starts to slow down and behaving oddly at times. It's a "feature" of Win-Doze.
Once things start to get bad, by far the best solution is to reformat your disk, then reinstall Windows from scratch. (Better yet, ditch it and switch to Unix!)