how to tell if a laptop can have two harddisks

"I know for a fact that laptops can have two hard drives. I recently upgraded a Gateway my friend has from Vista to Windows 7 and his laptop can have two drives. The way you could spot it on his is that it had two areas marked with a storage logo, looked like this:

So if you are going to be looking at the laptops physically that might be one way of making sure. If this is all done online, I know Dell allows you to select another hard drive during the customization part if this can be done. You can also type the model number of the laptop you are looking at in Google and the spec sheet will provide you with expansion information."

"They exist. The only ones I've seen are basically desktop replacement machines--big, heavy, not meant to be used in a portable fashion. They're meant to be hauled from point A to point B, plugged in and used. Most of these are gaming machines.

The only way you'll know about a particular machine is to look it up."