Acer aspire 5673WLMi windows files missing

Hello,
i would like to ask got anyperson can help me to solve my problem.i would appreaciate very much.
My laptop model is acer aspire 5673WLMi abd i use window Xp home edition.
My laptop shows

window could not start because of the following file is missing or corrupt.
<Window root>\system32\hal.dll.
please re-install a copy of the above file.


what should i do since that when i buy the laptop the window didnt come with the Cd ang i have no copy of it.
Just the back of the laptop have the window sticker and the product key only.
what should i do.
thanks.