|There is no such thing as Win Home or Win regular.|
There is Windows XP Home and Windows XP Professional. If you have Windows XP Home and wish to remove it to install Windows XP Professional you will need a Windows XP Professional CD.
If you have Windows XP Home I would stick with it as there is no advantage in installing windows XP Professional unless you intend connecting to a corporate network.
When you say you have no drive do you mean a CD/DVD drive or a hard disk drive.
Either way you are going to need both to install any operating system. Besides you are going to need more tha 40 Gbs of RAM for any version of Windows XP. 256 GBs would be the minumum with 512 Gbs putting you in the comfort zone.
So what version of Windows do you have now?