Yes .... you just put the cd in whilst in ME. you can then let it upgrade or choose the Advanced options and on reboot format and have a clean install.
While running your current version of Windows , insert the XP CD in the drive. When the setup menu appears, select "New Installation" (clean install) from the pull-down menu. Also, select "Advanced" and place checkmarks in the two boxes.
Next, your computer will start copying files and then reboot. At this point, select the c drive/partition . Select the option to "format" this partition using either FAT32 or NTFS.
After the drive/partition is formatted, XP will begin the setup process and install "clean".