I have a Dell Optiplex GX240 and I noticed that its "wake on LAN" capabilities only includes "on with MBA". I'm not sure about what the differences between MBA and PXE are. Is one better than the other? Any help would be appreciated. Thanks!

For a home user you would be more likely to use PXE as it is more supported from free tools. MBA, "Managed PC Boot Agent (MBA) Boot ROM Function Allows to Boot Diskless PCs Remotely" is normally used for enterprise or special systems. There is a chip on the lan that has sort of an OS, it is a network aware OS that allows booting and even power on and other functions that a system admin might wish to have. PXE is very common booting for local boot from a network as opposed to a remote operator starting the system via the lan. See argon technologies. The most simple way to setup pxe is with knoppix terminal services. If you want you can also try rom-o-matic to make a gpxe boot floppy to boot systems locally that don't have pxe or a rom chip. "Best Practices", Event viewer, host file, perfmon, are in my top 10