you can certainly reset the history by editing the registry (just go to the xolox directory in your registry editor and delete anything under the search history) however, if you are not sure how to do this then I don't advise it as it is possible that you can do irreparable harm to your computer.

as for completely removing the history I'm not sure if that is possible. I suspect that it may involve editing the program (which is not possible as the source code has never been released) but I could be wrong and there may be a way.

xg