can a prog. be installed on an external HD and then be plugged into another machine and run from there? or are some of the files written to the windows folder on installation and would need these files to run?
Some programs you can easily execute stand alone without installing them on to the machine you want to use them on. One I can think of is mIRC. Most tend to install system files to the Windows folder though and play up if the registry entries aren't there.