No you cannot. You would have to purchase a Windows 7 key or use the key displayed on the sticker to activate Windows 7. Although I would not consider using XP as there are no updates (for quite some time) and you are opening yourself up to security breaches on your system.
Hi, I have a Dell Optiplex 380 that I got second hand. When I look at the system configuration through the Dell service tag lookup page, I noticed that it had originally come with a downgrade to XP. On the computer, though, there is only a Windows 7 license key on the sticker. Can I use the Windows 7 key to activate XP in this case? The PC did not come with any accessories and the hard drive is wiped clean, so installing XP could only be a clean install through a download found online. Thanks.
Use Windows 7 License Key to Activate Windows XP When PC Shipped With XP