Computers Purchased with Preloaded Genuine Windows XP
In cases where you purchase a computer with a preloaded Windows XP, you also get a Windows Installation CD in addition to other CDs for drivers and extra stuff. However, most vendors do not ship the CD to save on money. Still, they offer a provision to reinstall Windows XP in case you need it. They save all Windows Installation files to any of the drives on the computer. The same folder will also contain the serial key of the product.
In most cases, you can easily identify the folder containing the Windows Installation files. Open the Start menu and click on Search (Windows key + pressing F). In the search window:
1. Click "All Files and Folders".
2. Type "i386" in the topmost textbox without quotes.
3. Click on "More Advanced Options" and click on the checkbox next to "Search Hidden Files and Folders."
4. Click the Search button to search for the folder where the vendor has kept Windows Installation files.
You may get more than one folders with the name. Open each folder, click UP button in the folder window to go up one level – to the folder containing the i386 folder. Look for the file winnt32.exe. If you can see it, this is the folder containing Windows Installation files. You can also locate the serial key in the same folder. Normally, it is a text file named "key" or "serial."
If you are not able to locate the serial, call your vendor immediately to get the serial key. You may also check out the packaging kit to see if the serial is printed on the box. Once you have the information about the Windows Installation folder and the serial key, I recommend you copy it to a location which you can easily remember.
Now that you know the whereabouts of Windows Installation files and serial key, you are all set to reinstall Windows XP without a CD.
However, simply running the winnt32.exe will not be equivalent to reloading Windows XP. Check out the article How to Reload Windows XP to understand what all will you may lose in case you wish to perform a clean install. Accordingly, backup those files. Once you backup the files you want, double click the file winnt32.exe to initiate reinstalling Windows XP without a CD.