I have Windows XP Professional. I have reinstalled it once when I got a new motherboard. How many times can I do this? If I install only a new HDD in my computer, should I still pass the 30-day authentication thing in XP for the 3rd time?

Do as infinity.

I thought the license restrictions were relaxed to only include OEM versions, though I'm probably mistaken.

Install as many times as you want. When it won't authenticate anymore, call support and BS them. They'll give you a code. They've done it for me twice now.

Pretty sure there aren't restrictions on Pro. Home is a one and done.

Nope, I've got a copy of home that came from a broken HP laptop. I just gave them a bunch of BS about how I was upset that they were giving me trouble installing XP on the laptop when I obviously couldn't have pirated it, they gave it to me free.

Then I ghosted the install after it was activated so I wouldn't have to do it again.

It will authenticate over the Internet three times. After that you will need to call them to get an authentication code.

When the computer asks for your installation ID, enter it in on the touchpad instead of speaking it, otherwise the computer might not understand you and will have to transfer you to a person who won't understand you much better. If you enter it on a touchpad the odds are much better you won't need to talk to a real person.

Don't know whether this counts as being against the forum rules..

I have no issues with using the activation crack on my perfectly legal version of Windows XP. I can't activate online and I don't want to have to beg microsoft for access to my computer every time I need to reinstall windows.

Also be wary that some phones just plain don't work with their system, for whatever reason.

I managed to get through to get my copy reactivated, and they hung up on me because they couldn't hear me. Switched phones and it was fine. :/

Right, my Windows XP is legit and I feel the same way. Meanwhile, everyone knows that pirates use that infamous XP corporate version and in that regard they don't have to worry about activation anyway. All activation does is cause problems for legit users.

I have no reason or desire to submit to Microsoft and waste my time by calling their activation system.

There's not much Microsoft can do about it, since they have no real authority or power over me since they are a corporation and not a government agency. The worst they can do is sue me, but so far that hasn't come up and I can prove that I've bought the software (I've saved the box, manual, and I have the receipt and original CD). Besides, they would have to prove damages to get anything; they ended up making money off of me instead when I bought the software.

in fact, I've had to buy windows twice for the same machine since the OEM restore CDS didn't work so I feel more than justified.

Is this my XP serial number?

No.

I reinstall XP at least once a day. Sometimes more if I have nothing else to do.