Can you recommend a free, preferably open source, auto-updater for Windows 7?

I run an ICT-based learning and resource centre at work. I’d use Linux if I could – I wouldn’t be asking this question otherwise!

We have various programs that are independent of Microsoft, and keeping them up-to-date is taking up too much of my time.

So, can you recommend a piece of free software that will treat installed programs on the computers in a similar manner to APT or RPM on Linux and keep them updated without me having to spend 3 hours in the resource centre individually updating each and every program on 15 machines.

Thanks muchly in advance of your kind helping!