i installed Ubuntu and found it unfathomable to get it to work for my daily use. There is help but you need to be quite knowledgeable to make it work. I strived some time but had to come back to XP. Sorry Sir, but that is my experience.
I had lost my XP original.I bought one from the sources mentioned above. Once I loaded the bought disc it worked well, As soon as I loaded then I found my missing xp disc. I have not bothered to load it.
Although I have issues with loading Service Pack 1 & 2. The service pack 3 was one the disc I bought. So I have SP3 but not others.
My guess is that SP1 & 2 do not matter if you have an anti virus installed. My XP is working fine though I am still struggling to find all the Drivers and especially those of your older applications and cards.
I hope it helps someone.