I installed Sins and Entrenchment and when I went to uninstall, I could uninstall entrenchment just fine (using the Windows XP - Control Panel- Add/Remove Programs method) but when I tried to uninstall Sins nothing would happen.
That's because Entrenchment is installed on top of sins, and by uninstalling Entrenchment, you've also uninstalled Sins. This is primarily because at the moment there is no way to "roll back" an Entrenchment install to get vanilla Sins back. I know this is pretty screwed up, but this is the current situation. It may change once Entrenchment goes out of Beta.
As far as I know, Sins itself does not add anything into the Registry at all. Impulse may, and the installer itself may (ie. Windows Add/Remove programs), but Sins itself does not add anything to the Registry.
At the moment, I am guessing that there is no Sins or Enthrenchment on your PC, although it may appear so in Windows Add/Remove programs correct?
So, I think your next step is to use Impulse to re-install Sins (no Entrenchment). Then, once it has been installed, you can do a proper uninstall of SOASE.
If you want to be able to switch back and forth between sins and entrenchment, then copy the whole Sins program directory before installing entrenchment. You can then rename/copy the folders according to which version you wish to play and it should work just fine.
wasting another hour waiting for Sins and Entrenchment to download and install
Impulse has a function called "Archive". You can archive an already installed copy of Sins, or you can right-click and choose "Download and Archive". Once you have archived it, Impulse will not need to re-download the program again if you choose "Open Archive".. You can even copy the archive file to DVD as a backup..
