Antivirus installed two operating systems

Hi all,

This is probably a no brainer but I couldn't find a short answer anywhere.

Is it possible to have my antivirus installed on two separate HDD on different operating systems in the same machine?

I currently have it installed on XP. But I am also running Win 7 64bit on another HDD with dual boot setup.

I have already used the other two installs on the kids computers

Any help would be appreciated