Problem Starting

I was doing some routine maintenance last night on my 2001 Ford Explorer. I changed the air filter and, this morning, I can't get the engine to start.

The housing for the air filter was rather difficult to get out of the way and required a little "elbow grease" so that I could replace the filter. I wonder if, while doing so, I loosened or disconnected something else without realizing it.

Now, the engine will roll over, but it won't start. I'm not really sure what the problem is as changing the oil/air filter is usually about as far as I go with automotive repairs.

However, now that my explorer is in my garage and won't start, I'm wondering if anyone might have a few quick suggestions for me to try so that, hopefully, I won't have to get it towed to the shop.

Thanks, everyone.

If it is related to the filter change, about all it could be is maybe some of those electrical plug-ins into the hose that had to be removed....got loose.