If you want to install x64 based windows you can use these methods to know your system capability of x64 based OS’s.
To find out if your processor is 64-bit-capable in Windows 7 or Windows Vista, do the following:
1. Open Performance Information and Tools by clicking the Start button, and then clicking Control Panel, open Performance Information and Tools.
2. Do the following according to windows installed on your system:
In Windows 7, click View and print detailed performance and system information.
In Windows Vista, click View and print details.
3. In the System section, you can see what type of operating system you’re currently running under System type, and whether or not you can run a 64-bit version of Windows under 64-bit capable. (If your computer is already running a 64-bit version of Windows, you won’t see the 64-bit capable listing.)
To see whether a computer running Windows XP is capable of running a 64-bit version of Windows, do the following:
1. Click Start.
2. Right-click My Computer, and then click Properties.
3. If "x64 Edition" is listed under System, your processor is capable of running a 64-bit version of Windows. If you don’t see "x64 Edition" listed, your processor still might be capable of running a 64-bit version of Windows. To find out for sure, download and run the free Windows 7 Upgrade Advisor from the Windows 7 Upgrade Advisor webpage.
Enjoy…