Windows 8 = 64-bit. No 16-bit installer, so even if an application would work in the virtual XP machine, there's no easy way to install it short of taking before and after snapshots of a clean XP box and installing your app on it, then hoping it translates to 64-bits.
We have XP boxes that talk to specialized PCI cards. While there are some MBs you can buy with PCI slots, they're getting harder and harder to find. You can't get newer Windows drivers for the old hardware, and forget about finding compatible Win 7/8 drivers for the PCI cards.
All this means is the decision made 8 years ago to "save money" by using Windows-based PCs for Process Automation is going to cost us an equally large amount of money in order to replace everything.
Say what you will about VMS, but those systems are still running 24x7 20+ years after they were installed. Now, the aging DEC hardware can be swapped for an up-to-date Intel-based server running emulation software, but there's no reason to replace the application software if it does the job it needs to.
Microsoft should have designed an Real-Time OS decades ago, but they've gone all touchy-feelie now.