We're looking for something to monitor around 30 remote laptops that are constantly out on the road, never returning to base except for when there are serious hardware faults that need repairing. These laptops won't always be connected to the internet, they'll have mobile broadband and may work offline most of the time. They will be running a mixture of Windows XP, Vista and 7 and there is currently no server setup.

We're primarily interested in making sure that Windows Updates and antivirus updates are happening, and I guess we should also be monitoring remaining disk space, what software is installed and ideally hardware health. It might also be nice if we could gain remote access to perform work on them.

My main reason for wanting to monitor them is that it's going to be a real pain to get them back to base if anything goes wrong, so I want to be proactive in ensuring they last as long as possible.

Can you recommend what I should be monitoring to ensure a long life? What tools would you use to monitor and maintain these computers?