Windows Xp Professional Invalid Key

I'm taking it that you have copied the Product Key off the COA correctly as that can be a nasty job quite often to read the correct characters. I use a Jewellers Loop for that job as my eyes are no where near as good as they used to be.

But if the Product Key is correct and you are using the Restore CD provided by HP they have provided you with an incorrect COA for that system and it's then up to HP to rectify the problem.

While the Key may be a valid Key it might not be a valid key for that particular version of XP that you have so if you are using the Restored CD from HP they are at fault and it's up to them to come up with a fix.

However if you are not using the HP CD then you are very unlikely to get it to work with that Product Key as you have a different version of XP to what that Key applies to. It doesn't matter if you have XP Pro/Home with SP2 or whatever HP uses something similar to a volume license copy of Windows so they don't have to supply the complete Windows package just the necessary drivers and other parts of XP that is used on their hardware. If you are attempting to reinstall from an OEM CD the HP Key [b]Will Not[/b] work with the OEM product and you'll need the HP Restore CD to work off.

If you have everything correct look at the COA under some form of magnification and read off the characters while someone else writes them down & then get them to read back the 25 characters to you. Things like C & G and O & Q are very easy to mix up and you could quite easily have the wrong Key for that particular Restore CD. This is very easy to make a mistake doing and I've seen it quite a few times in the past as well as doing it myself.

Col

Hi this new HDD is it an exact match to the old?
Eraser is correct.
Your original hdd probably had a hidden partition and the xpcd they provided was not a true install disc. But rather a recovery disc to access the hidden partition.
Hp brands like Del and Compaq have specific drivers that suit that particular mainboard.
You could consider buying yourself a new xp pro cd not a HP version and start clean install.
This then would nolonger be owned by HP and if you have problems with any future HDD you can just clean install again.
You'll need the mainboard specs so that you get drivers if they are not natively on the xpcd.
http://cnet.nytimes.com/HP_Omnibook_510_Pentium_III_1_13GHz_256MB_Wi_Fi/4507-3121_7-9496116.html

What condition is the old hard drive? Is it readable at all?
If you could slave it and ghost a good functioning operating system off it then image it back onto your new hdd using Norton Ghost you maybe be back in business.
http://www.argentuma.com/backup/software/norton-ghost.html
I wish you well