Belarc alternative for remote execution

I have a domain full of computers. I need to find out the microsoft office keys and adobe product keys and whatnot. Belarc does a fantastic job, but I can't seem to run it on a remote computer. I would love to find something that I can run silently on my computers on the domain so that the client doesn't even see it. PSexec doesn't really work without client input. I can remote into these machines and run belarc myself but this requires me to set up a schedule for the client to stop working and let me run it. Anyone know of anything? also free or cheaper than belmanage.