When I bought desktop from computer store, I found only Vista installed. But most of time I need work on Windows XP. Then I tried to install Windows XP on my new desktop so that I can have a Dual boot PC.
Finally I done it successfully. I wrote the steps as the folloing:
1: download the tool “VistaBootPro 3.3” (when I used, the version was 3.3) in your Windows Vista, save it to some folder or other place you own know;
download from this page: http://www.vistabootpro.org/
2: download .NET 2.0 framework into the same folder or other place you own know;
3: prepare all drivers of your PC for WinXP;
If your PC has already 2 or 2+ partitives, do the following steps, otherwise, you have to allocate a new partition in your PC for installing Win XP.
4: Using a windows XP disc to boot your PC and install XP in your new partition;
5: install .net 2.0 framework in your new XP OS;
6: install VistaBootPro 3.3 in your new XP OS;
Now you will find you can not boot into Windows Visat.
7: Open VistaBootPRO, ignore the prompt to backup your BCD. Go to the System Bootloader tab, select “Windows Vista Bootloader” in the first section and “All Drives” in the second section, then click Install Bootloader . and then, go to the Diagnostics item ( on the menu bar ), select “Run Diagnostics”. VistaBootPRO will default back to the Manage OS Entries page . Now you will see the entries for “Earlier versions of Windows” as well as “Microsoft Windows Vista”.
(you can change boot name for windows xp to your own name like “Windows XP Pro” when you using VistaBootPro setting)
8: Restart your system and select the operating system you would like to boot to.
9: install drivers in Windows XP if need;