As a test, I would shut down (power off) the computer and disconnect all USB devices including hub, except for standard keyboard and mouse if normally used. Do this to reset the shuffle
Start up the computer, run iTunes, and connect the shuffle to a direct USB port on the computer.
If that does not help... Since it worked previously on the same computer with no changes to software, we'll assume the cause is not software-related (Windows or iTunes). Then, the remaining possibilities are:
Problem with USB port - You can rule this out by connecting something else to that USB port, preferably something similar like a USB flash drive.
Faulty USB docking cable - You'll need to try a different USB cable or use that cable with another working shuffle (3rd or 4th gen), to rule this out.
Problem on shuffle - If the problem is not the USB port or the cable, it is likely to be on the shuffle itself. If the shuffle is less than one year from purchase date, it is under warranty. If there is an Apple Store nearby, you can make a reservation at the store's Genius Bar and take it there and have the tech support person there take a look.