I tried it with an update from a K6-2 500 and Ali chipset mobo to a XP1900+ and A7V8X mobo. I was quite funny. Just as if Win XP didn't know what it was doing, refusing to install my drivers or anything else (it locked). So definitely go for a clean instalation. It will take less time than trying to repair XP (if posible)
Romania is a beautiful country, unfortunately it's inhabited.