iTunes not working - Two users on one Pc. Both have own iTunes accts and music (held in different locations).

Two users on one Pc. Both have own iTunes accts and music (held in different locations). All worked fine until few months ago and recently one user has not been able to get iTunes to start. An Error code is no help. Factors I've discovered include:- 1) iTunes was installed via Microsoft Store. 2) Cannot install new Itunes from Apple as the system tells me that the Store installed version must be uninstalled first. 3) iTunes does not appear as a programme in "Control Panel - uninstall" - so, can't uninstall it!. From this forum understand that the store installed software is "all over the place". Tried control panel / right mouse on start uninstall, doesnt work either.The other user is operating iTunes as normal, just don't know where the software is to try and proceed to remove it. Tried to reinstall/update via the store and it fails, telling me Windows update is disabled. (Code 0x8007422) It isn't in every sense of the word, ie Windows, Apps, store access. Troubleshooter - no success. iTunes does appear as an app on CCcleaner but will not uninstall. I'm STUCK, anyone any ideas?