I currently have a dodgy old P3 (500MHz) and recently bought a P4 (2.8GHz). I want to transfer the HDD from my old computer to my new one. Ideally, I hoped that Windows would boot straight away on my new PC off the old HDD. Obviously, life isn't so simple. Is there a work-around or do I have to bite the bullet and re-install everything separately on the new PC? Any help welcome!

You can try a repair install. That will reinstall Windows but keep all the old settings but in the process load the necessary drivers and software for the new computer. To do a repair install, boot from you Windows XP CD. Ignore the first repair option, that will take you into the repair console which you don't want. When to installation asks you if you want to install windows, then select the repair option. You will need the key that goes with the CD and you will also need to reactivate. Depending on how long it was since that particular installation was activated it should be a straight forward process if it was more than six months ago. If it was activated withing six months you may have to phone Microsoft to get an new authorisation code. Stuart

If the version of XP on old PC was OEM ie DELL, HP, IBM etal, then the KeyCode is tied to the PC. The repair install will only work with Corporate or Retail versions AFAIK

The repair install (actually a repair Setup)will work with an OEM full XP CD too, as in, one you purchased at the same time you bought hardware.

I agree.......the repair install should do the trick.....Ive done it a few times. Windows does a nice job of keeping things in order. Good luck....let us know how it worked.