I agree. If your computer still works, you can use it. As long as you are not doing anything crazy in the Internet and have good antivirus and firewall, your chances of getting in trouble are not very high..
Virtual machines are not always as good as they are painted to be. Often it is very painful to run a program in a virtual machine, if it is possible at all, that is, because not every program runs in a virtual machine. I have given up trying to run virtual machines, even the "good," professional, purchased ones, not only the free ones. They all have a list of programs that run well, others that run so-so, and a longer list of programs that don't run at all, and chances are that your program will fall into one of the last two categories.
What I have done is switch to Windows 7 for almost everything, and buy a couple of refurbished Dells with XP for my older programs, because sometimes new computers don't run XP that well, even if you have dual boot. And even XP mode in Windows 7 is not as great as running a native XP, because it is also a virtualization program, so for XP programs, the best thing is to run native XP: nothing comes close.
Regarding OS-X and Linux, they will not run programs for XP or any other version of Windows, unless you run a virtualization program, which, as I said above, are slow and painful, if they run at all.
The principle I have learned after many tries with virtual machines in Windows, OS-X and Linux, and I mean countless hours and weekends struggling with different distros of Linux, is that every program runs well only in the OS for which it was written. Virtualization programs are not a good answer for this problem, at least for now. They may get better in time, but they are not there yet.
Your best bet is to stay with native XP or spend the money to get the newer version of your program for Windows 7 and 8, which eventually you will be forced to. Don't get into the game of fiddling with virtual machines: you will regret it.