Triple+ Monitor Setup, tricks for success

Problem:
You want to use more than 2 monitors

Caviate: 
Laptops, this probably doesn't apply to you. Laptops should use a USB 3.0 Video Card because I've never seen onboard graphics cards able to do more than 2 monitors. Note, that USB videocards SUCK - they're laggy. Great for displays that don't need to be updated often, like a map or webpage - not for fast-paced things!

Solution 1:
The on board video built into your computer can sometimes be activated in tandum with a video card. These options vary between vendors, but generally:

• Must be similar brand and chipset (I had a motherboard which would only pair to the Radeon HD GfxCard Chipset)
• Is something which is advertised- generally it's not a hard to find feature. This usually means the on-board graphics are decent and not bargain-bin (IE you may see Intel 4000 gfx as a bullet but you'd see "1GB AMD R9 600M" as a feature.
• Exists as an option in the graphics card control (CCC or whatever Nvidia uses) in windows
• AND / OR a bios option

Solution 2:

Buying a graphics card. 

Make SURE it has at least the number of ports as you have monitors you want to use! Not every graphics card, even if it has the physical ports, can support 3 monitors. Generally, read the reviews - newegg allows you to ask questions, do so!

There are two types of setups:

1. Eye Finity or Stretched Display: This makes it appear to Windows as though you have one really large monitor with an ultra high resolution. This is the less resource intensive of the two options. If you're having trouble getting things working as independent monitors, start digging this route. Downside: it's not great for normal computer use because windows span monitors - but it's practically the norm for gaming.

2. Independent Monitors: Each monitor is recognized and treated as independent, you can control the resolution on each and windows recognizes you have 3 monitors. Windows may not be able to set this up and you may be forced to fidget with settings in the gfxcard control panel. 

Wires:

Adapters can complicate things and it's generally best to avoid them - at least for troubleshooting purposes. Some cards require an active adapter for more than 2 monitors. Active adapters are essentially adapters which are powered.  But in that instance, I think eye-finity will work. 

Troubleshooting: 

When things aren't working, take it back to basics:

Uninstall all AMD or NVD software & drivers:
First, use the control panel to uninstall gfxcard software, then boot to "Safe Mode" and run Guru driver sweeper- it will remove traces of those drivers and prevent windows from installing hardware automatically. 

Reinstall, Properly: 

If you have an AMD or intel motherboard - you may be missing some drivers after the uninstall. I know this is really an issue with AMD.. So before you install the video card, find your motherboard model (hint: use Piriform's Speccy) and the correct drivers for it. If you're using a generic motherboard, both chipset types make auto detect systems which can get your chipset up to speed -- but outside that:

When troubleshooting, in most all cases, "auto detect" is not the way you want to go. You want specific drivers - so you have an r9 280x - which company makes your card? Do they have driver downloads for this card on their website? If so, you should use those!

If your graphics card is made by the same chip manufacture as your motherboard (AMD/AMD or Intel/Intel), this can cause issues - when troubleshooting, only install the basics you need to get up and running, then elaborate. 

Using AMD graphic card installer package, when you choose express, installs AHCI, USB, SATA drivers, which are related to your motherboard. When you're using drivers based on different time periods (for example, your gfx card manufacturer has version 13.0 as recommended, but your motherboard is on 14) be limited in your install scope. Only choose to install crucial items. (GFXcard driver, CCC-- that's it!)

My reference:
A job today with a powercolor r9 280x which was touchy to get working with three monitors. I had to remove the card after I caused it to lock on boot - then remove everything AMD, reinstall chipset drivers, then specifically install the drivers powercolor mentioned. Using 2 Mini-displayport to HDMI and one HDMI wire I was able to get three monitors working in both modes without problem.

edit:
Remember that driver sweeper prevents windows from automatically installing hardware - this can become a burden and so there's an option to turn it back on when you open the software.