Evandv,
You wrote, "We have to buy a xp windows because our system is crashed."
Just because your system crashed does not necessarily mean that you have to buy an entire new license for Windows. If the computer has a Certificate of Authenticity for Windows affixed to it, then it's very likely that what you need is a set of Recovery or Reinstallation Discs, and most of the time the computer's manufacturer is the source for these.
Please tell us about the Certificate of Authenticity (CoA) for your Windows. Tell us:
1. What edition of Windows XP is it for, Home, Pro, Tablet, or Media Center?
2. For installations of XP that came with the computer (OEM):
2a. Does it read "OEM Software" or "OEM Product" in black lettering?
2b. Or, does it have the computer manufacturer's name in black lettering?
3. For installations of XP purchased at retail, does the retail package have the CoA on the outer boxtop, and the Product Key printed on an orange label inside the folder that came in the box?
4. DO NOT post the Product Key that may be printed on the CoA.
Please visit this page for detailed information and images of CoAs: http://www.microsoft.com/resources/howtotell/content.aspx?displaylang=en&pg=coa
For great advice on all topics XP, visit http://www.annoyances.org/exec/forum/winxp