as you can read in <a href=”http://www.oracle.com/technology/tech/windows/faq.html”>this article</a> you cannot install it in WindowsXP, hereafter an excerpt of the article:
For AMD64/EM64T platform information, refer to this certification matrix.
Windows 2000 support indicates support for Professional, Server, Advanced Server, Datacenter editions.
Windows XP support indicates support for Professional Edition (32-bit) and XP 2003 (64-bit Itanium). Windows XP 2003 is supported for Oracle 9.2 and 10.1 only. Microsoft is discontinuing support for Windows XP for Itanium.
Windows Server 2003 support indicates support for Standard, Enterprise, Datacenter, Web editions (32-bit) and Enterprise and Datacenter editions (64-bit Itanium).
Windows NT and Windows 98 have been desupported by Oracle.
Oracle Standard Edition support includes support for Standard Edition One.
Consult Oracle Metalink for updated operating support information.</i>