ClearOS is typically run on a server or dedicated hardware like a ClearBOX. However, you can also run it on a standard laptop.
If you don't have a CD/DVD drive, see ClearOS USB installer.
Unless you use ClearOS only as a server (and not as a gateway), you will likely need a second (or even third) network interface. Since laptops typically have only one NIC, you should purchase a USB-NIC. See USB Network Cards.
If you are installing at home, you should configure your router to make the ClearOS instance be in the “DMZ”. Of even better, transform your ClearOS instance into a wireless access point