Try downloading from one of the alternative sites here ==>
calibre - Download for Windows. ISPs have been known to cache corrupted copies, the alternative sites are HTTPS which thwarts their caching.
If that doesn't solve the problem I suggest you run a decent standalone virus scanner over your system - I favour Malwarebytes. And then use the
[Microsoft] System File Checker tool to repair missing or corrupted system files.
If you want to try another .msi, this one is relatively harmless -
BowPad - Stefan's Tools - it's a text editor tied with pretty ribbons
BR