Hi everybody!I have problem to get working wireless connection on my 6 years old HP with Windows XP.And I  am thinking ,what about Powerline Ethernet Adapter.I live in a single house.That would work,right?What the difference in signal strength (signal drop).If my router is 56 Mgb/sec-what do i get at the other end?Is this WAY good enought?The AC Power Ethernet Adapters have a bad rap, but are suppose to work. The signal quality is different from your Wifi signal quality - it will either work or won't.

The 56mb figure you reference is the Wifi max speed at full signal... this is usually much faster than your Internet connection. The AC adapters probably try to get you 10mb or 100mb which are the common physical Ethernet speeds.

How FAR from your router is your laptop? It would be better to use Wifi if you could... Yes, you're much better off using just the pair wires rather than to attempt power line or wireless connections. The power-line network connection is for situations where you absolutely positively cannot pass a wire under a window under a doorway or make a very tiny hole in the wall.
Of course, Ethernet cable is rather thick, about the size of your little finger. But it's possible to have a suitable network using just the two pair of very thin wires. This type of connection can sustain 1 Mb for very long distances, like over 500 feet. For shorter distances, say under 100 feet you can get up to 10 Mb per second.
There is a company that goes by the name of t "Two Wire" and they got their start making USB devices that would tie into a two wire or four wire telephone cord. Any kind of wire works, I used a very long extension cord, with suitable connectors of course, and it worked very well from my barn over to the RV trailer where my daughter lived for a while. However, it is not Ethernet compatible, so you have to set up network sharing for the thing to get you onto a local area network.
Here is the link for the company:
http://www.2wire.com/
Notice that they make many different kinds of network products. The two wire interface was one of their earlier things.
First thing I would do is post all the information here about your wireless network, and the problems it's having.  If that can be fixed that would be simpler and cheaper that buying new hardware, running or new cabling.Wireless would work better for you. If you're having problems you just need to see if they're from the wireless adapters on the computers or if it's a problem with the router.I just recieved new N-router from Comcast and i`m going to install it.Then I`m going to check wireless adapter and set it up with new router ..Maybe will get some luck .Otherwise will run wire.Just to add to the thread, I've been using powerline adapters for a year or two now ... no issues.  I'm in a situation where I can't run an Ethernet cable, otherwise I would.  The powerline adapters have been great for me, no issues whatsoever.  Just like an Ethernet cable really, no noticeable added latency or speed issues. Here is another viewpoint.
Quote

Devolo dLAN 200 AVeasy powerline adapter review
 By: Hilbert Hagedoorn | Edited by Ian R. Barling | Published: March 22, 2010 
So the other day I had to set up a little network for a friend of mine and the entry point of the ADSL line and router were located in the bottom of his house. His two PCs that needed to be connected where all the way on the second floor. Now, to create a network one can do SEVERAL things. Take a long CAT5 cable, drill holes though the floors of the house and route the cabling through it. Sure, BEST performance... but not really sexy-looking in your spanking new remodeled house.....
 more-> http://www.guru3d.com/article/devolo-dlan-200-aveasy-powerline-adapter-review/

...For several years, some companies have tried some way to use the outside electric lines to carry internet service.  Since outside electric wires are unshielded, they also act as giant antennas, and create strong interference to low frequency HAM radio.  Because of the interference, it's mostly a dead issue, but some companies are still working on it, and it seems to pop up every few years.

Broadband Over Powerlines has been in development for many years, the main issue being getting the signal to pass through all the transformers.  Utility companies have viewed this technology as the Holy Grail.  Since they already have the infrastructure in place, the cost to become a major ISP player would be relatively low.