MantaRay, one of the problems is not the age of the PC but if drivers are available.
Every hardware component in your PC (sound card, graphics card, and all sorts of others) need DRIVERS. These are small software programs that tell Windows how to work with the device.
Normally there is a new driver for each release of Windows (not always but usually) that is written by the people who make the sound card, graphics card etc.
Of course as hardware components get older the company dont bother to keep upgrading their drivers.
So for example your sound card may have a driver for XP, probably for Vista, maybe for Windows 7, but maybe not for Windows 8 or Windows 10.
So the problem is if you try to go up to Windows 10 you may find that there are not drivers for some of your hardware components, so they wont work properly.
Also hardware has come a long way since XP came out and almost all the components inside now run faster (CPUs, memory, BUS speed etc).
So putting Windows 10 on an old PC is like trying to put a new car engine inside a Ford Anglia.
So bite the bullet and get a newer PC.