Windows version: 1607 64-bit (I have feeling it should be a higher number, but Settings/Update says it's up-to-date. The computer is: Processor: AMD FX-8350 8-core RAM: 8.0 GB Trying to open the built-in calculatar app now results in this message: "This app can't open - Calculator can't be opened using the Built-in Administrator account. Sign in with a different account and try again." The above also applies to the weather app. I tried downloading MSN Weather advertised as "Weather app for Windows 10". When I clicked on the download button I got "This app can't open." It appears that the Windows Store is similarly affected. Under Settings/Accounts my account is "Local Account - Administrator". As such I should be able to access all apps on the computer. I'm the only one using this computer, so I have disabled the Lock Screen, and Log-in procedure, so booting up gets me straight into the Desktop, bypassing log-in, so there is no way to log on to another account as suggested. Before the latest update (late last week) all was well. I've run sfc /scannow, but nothing was found. Has anyone any idea what's gone wrong, and how can I get it put right.