reinstalling absolutely everything from scratch should put your mind at rest that the phone isnt the problem. uninstall all drivers for the device along with the mobile associated software you got with your phone. most phone companies should have the latest software and/or drivers to download from their website, so losing your disc shouldnt be a major problem. if there is nothing available try emailing them to send you the software, stating it was lost. if a reinstall of the software doesnt work, or even a system restore to a time it was definately working, and its not a connection/cable problem, then your phone is most likely jiggered! the only other thing i can think of is you may have installed new software, unrelated or not, which may have interfered with your pc being able to recognise it..
Windows 10 Home vs Windows 10 Pro comparison: Here are the extra features you get in the Pro version