How do I uninstall versions of Win Xp, i.e Windows, windows.0, windows.1, etc.

Sorry, I don't understand your question. There needs to be an operating system installed on your computer to use it. You can format the hard drive to wipe it clean, erasing the operating system, or you can upgrade the operating system to something such as Windows 7.

The system I am running is listed as
Windows.4.exe

Windows NT 4.0 ? There are no windows.exe files...
Anyway, formatting the drive works to uninstall, but copy out what you wish to keep.
Or... do you have a system folder named Windows.4? It may be that a Recovery operation failed and created multiple Windows folders; if so, then this is the method to follow.. http://support.microsoft.com/kb/888023
Remember to copy out files you wish to keep.