How can I safely uninstall a program without an uninstaller?

[ViolinIsLife]

Computer Uninstalling problem!

I have a question of how to uninstall a program safely without some kind of uninstaller shown in Add and Remove. For example, I installed cigwin in my computer, and I don't know how to install it since there's no an unintaller associated with it. Thank you very much for whatever advice!

 

[Luminous Blob]

Just delete the root folder and all its subfolders, as explained here:

http://cygwin.com/faq/faq_2.html#SEC20

 

[-Job-]

Basically when you install a program in windows you do the following:
. copy some files over to program files directory
. copy some libraries (dlls) over to either windows or program files directory
. add some entries to the registry. If you selected to install for every user, then changes are made to HKEY_LOCAL_MACHINE, otherwise to HKEY_CURRENT_USER.
. create shortcuts and start menu entries.

You can manually roll back the installation, but you will probably find yourself manually editing the registry which is a dangerous practice.
There are tools that clean the registry and look for orphan dlls, such as Ashampoo's WinOptimizer: http://www.ashampoo.com/frontend/homepage/php/index.php?session_langid=2
which you would use after manually deleting the root folder.