My system is dual boot, Win-XP Professional (32-bit) an Win-7 (64-bit).
I have XAMPP installed on my XP OS (C:/XAMPP).
I want to use the same htdocs directory for testing the php on my windows also.
But when I am installing the XAMPP on the same directory, I am getting this error.
Important! Because an activated User Account Control (UAC) on your
sytem some functions of XAMPP are possibly restricted. With UAC please
avoid to install XAMPP to C:\Program Files (x86) (missing write
permisssions). Or deactivate UAC with msconfig after this setup.
Can someone please help me in resolving this thing?
Thanks.

First : open Start Menu -> Run.. and type “lusrmgr.msc” inside. In the opened window, click “Users” on the left menu, then double-click on your username in the middle and then select “Member Of” in the opened window. Do you see “Administrators” there?
BTW you can try installing XAMPP in another directory, then open php.ini and set the VirtualDirectory parameters to point your previous XAMPP htdocs folder.