Is there a program that can backup installed programs?

I need a program that can backup and restore other programs that have already been installed. I no longer have the installer for those programs, and I cannot seem to find those programs. Could anyone give me a link to some software (Preferrably free) that enables me to either backup programs that were installed or repackage programs that were installed into one installer?

Thanks in advanced!

I'm sorry, but I don't think that what you ask is possible. I make it a habit to keep the installers for any programs I download in a file on the desktop. It uses up some extra memory, but has proved useful on more than one occasion.

I'm not sure if this would help you, but you can get software that takes an image copy of your hd. This means os, apps, and data, so you can restore to a point in time in case of disaster. Wouldn't allow you to take an app to a different computer. I have a lot of apps installed on my computer and don't want to reinstall everything if my system goes bad, so I have an image copy and data bkups. I can restore from the image copy and come forward with the bkups.

I use Acronis True Image, but there is DriveImage, Ghost, and lots more.