|Did you re-install XP HOME and then get that error?|
If yes, which XP CD did you use? Was it an XP HOME OEM CD or other?
Is the key you used the one printed on the COA label at the back of the laptop?
Is that key on the label for an XP HOME variant or other?
As it is is an ACER laptop, I would suggest that it is an OEM laptop and therefore would have originally had an XP HOME or PRO OEM SLP install on it.
Assuming it was originally shipped with XP HOME SLP installed and my assumption is correct and you used the serial at the back of the laptop then you should not get an invalid error message, rather you would get an opportunity to carry out activation by phone.
The error to me suggests that you typed the key in wrongly.
If it is an OEM laptop which came originally installed with OEM XP HOME and you are using an OEM XP HOME CD then you can re-install OEM XP HOME and use the Microsoft Standard OEM key to affect/simulate an OEM SLP install which does not require activation. The key to use is:
NOTE: The key is for OEM XP PRO but may also work on OEM XP HOME - If it does not PM me and I may be able to help identify the correct OEM SLP key for your situation.
See here for more detail:
If my assumptions are incorrect then you need to answer the questions posed in order to be correctly advised and/or helped.
Additionally as pointed out in post #1 you should NEVER post your keys.
The key I have posted is different in that it is a Microsoft provided standard key designed specifically to solve these kind of cases and is available publically and has limited use (i.e. cannot be pirated).
☺ When everything else fails, read the instructions.