When a document, made in ms-office version x, doesn't look correct in ms-office version y, that's normal!
I don't recall ever seeing that, although I think the graphics drawing in M$ Orifice was buggy 25+ years ago.
I'm not so sure about WinXP. If memory serves me well, at some point I tried to install WinXP on a computer with a direct internet connection and it got infected faster than I could download the updates. Nowadays it is crazy to think that at one point most PCs (even the ones in offices!) had direct internet connections with public IP addresses.
You may be right. Certainly win2000 did that. But nobody with a brain would run directly like that today

I think when I was running with a Cisco 803 ISDN router maybe 25 years ago, there was no NAT as such but there was a firewall in the IOS config... of course Cisco made sure nobody could understand IOS

WinXP is 100% solid. I have machines running 24/7/365 for years. Internet connected, behind NAT, polling a POP box and doing "specific stuff" and sending out automated emails. The main issue with XP is that it 100% destroys an SSD after 1 year of that

It trashes the start of the HD. Win7 is OK.
I know we did the "NAT attack" thing here in the past but really it is so contrived... you might be able to do it on a very specific individual whose equipment and habits are known.
I am 100% convinced that "business" could still be on win7-64 perfectly fine, if not forced by
- due diligence M$ support box ticking (an absolute override of everything in big organisations)
- some apps forcing it; mostly browsers (not Orifice; 2007 does everything needed) and in turn many websites
There is a reason why apparently many corporates keep win7-64 and M$ support it with updates (accessible to use via Simplix

). Simplix brings win7-64 up to win10 sort of patch level. Some oddball things which stopped working on win7 (some videos, curiously) but worked on win10, worked fine on Simplix-updated win7.