Does organic compost have a "shelf life"?

Four or five years ago, I purchased a huge shipment of organic compost which had pride of place in my suburban driveway for quite a long time. After I used most of it, I moved what remained of the pile into four or five 30-gallon trash cans, and through a combination of chaotic life events and general senility, managed to forget about it. Now that it's resurfaced, I'm wondering if it still has any beneficial life in it. It seems very dry and doesn't have that rich humus-y smell, but there aren't any signs of insects or fungi (not any immediate sign of worms, either, though). It's probably been in the trash cans about 18 months or two years.

Tried to find some info in my reference books and via a quick search, but didn't come across anything specific. Any wisdom much appreciated. Thanks!

If the compost has dried out completely there will be very little, if any, micro-organisms left, but it will still make a useful mulch if you can re-wet it and maybe add some compost with a bit of life in it from your compost heap (if you have one).

Good idea; I'll give it a try as mulch. Thanks for the help.