Ping in PC environment.
https://technet.microsoft.com/en-us/library/cc737478(v=ws.10).aspx
The fact that bonjour has found the printer means it should ping.. so ping it. Most important is to ping by name.
Look up the name of the express in the airport utility which should be installed on your win7 PC.. it is always worth having this.
Open the command window and simply ping the express by name and IP.
If it fails.. how much time do you really want to waste on this.. because I assure you .. fixes will not be simple magic silver bullet.. (unless fired into the guts of printer which is then dumped in the ocean and you buy a new printer that has network).
You are trying to print to a device.. that has an IP.. make sure the IP never changes.. and then setup the printer port to the IP of the express.
https://www.youtube.com/watch?v=qTN1g846dRE
This video covers exactly how to do this.. it says extreme but the express is the same thing.
Next time you buy a printer.. buy a fully network capable printer.. it is not worth messing with USB.. USB is a local device.. and is not intended for network sharing. The cost difference these days is minor. A couple of sets of toners cost more than the printer.