In the past I thought with a OEM version of Windows you could only install it on one system and if you change some things in that system the license became void? Well now that I put a new mobo in my computer I tried to install XP. The activation failed and I was forced to call Microsoft, but they just activate it again for me.

So did the policy changed or was it always like that? Not asked this to the person on the phone, as I didn't want him to get second thoughts. The OS is installed only on one system btw.