VB 6 Retirement

Good day,

I started learning to program in C/C++, then found myself needing to
write a
lot of macros in excel, so I adopted VB 6.
Now, after recently shelling out a few hundred to get the professional
edition, I find it hard to move to .NET without reaping some sort of
ROI.

Can you please inform me at what point a program compiled in vb 6 will
not
be able to run on a windows system?

I am an accounting professional in a small company, I would really hate
to
one day realize we cannot upgrade windows or have to re-write all the
apps.

I am seriously considering returning to C++ for the stability it
provides,
but find myself struggling with the RAD/ ease-of-use nature of VB.

Please Help