Registered RAM contains an extra chip that sits between the memory chips and the memory controller on the motherboard. These extra chips act as a buffer giving the data a place to sit while the memory module prepares to use the data (writing or reading). By doing this, the buffer is in effect acting as a repeater or amplifier. This allows two things. It allows a system to support more RAM slots and also allows a module to contain more chips. It's like trying to shout to someone 100 yards away, if someone were to stand between you and the other person your shout (data) would get transmitted easier. This reduces errors caused by excessive drain on the memory subsystems power.

Also note: ECC is not the same as registered RAM. It is true that almost all registered RAM is also ECC due to it being designed for mission critical applications like servers. However all ECC memory is not registered. It is very easy to tell the difference, if a module has an even number of memory chips it's likely non-ECC, if it has a odd number it's likely ECC, and if it has an odd number and a few extra chips that do not look the same as the memory chips (usually smaller chips near the modules connector pins) then it is likely Registered ECC RAM. There are going to exceptions to this rule, but it applies 99% of the time.

Now to answer the question: Will it work for you? Unless your motherboard specifically states it supports Registered or Buffered memory, then it most likely does not support it. Registered RAM is designed for Servers and high end Workstations, so most standard desktops do not support it. Also you can never mix Buffered (registered) and Unbuffered (normal) RAM in the same system. So if you are upgrading your RAM and you are buying Registered and your old RAM is not, then you'll have to remove the old RAM for it to work.