How to connect dual monitors on Lenovo computer?

I just got a Lenovo pc and I'm looking to have to dual monitors which would both display different windows. I only have a VGA port and a couple USB ports is there some kind of adapter I can use? I have the dvi cables needed for it just need to have them hooked up somehow. I opened up the pc and it looks like I can't install a second video card.

USB to HDMI or VGA or DVI type external video adapter, $40 is a lot cheaper than a $150 Matrox box. I use the Iogear brand, just fine.
You could get a different video card to put in your desktop box. Many cards can control up to 6 monitors.

You just need to be able to connect it to the monitor. Doesn't matter how. Go to the charms and select devices and then project. Then click on the extend option. Your pc should do the rest

A few choices.
1. Get something like -> Matrox Dual Head To Go unit this will make it like you've got a dual port graphics card, so you can have different things running in different screen but its not cheap
2. http://www.wikihow.com/Set-Up-Dual-Monitors here is a guide for doing dual monitor.
3. If this is a PC/desktop change the graphics card to a dual/multi port graphics card. (but this depends on what card you have already, and what sort of budget you have)