laptop to tv via hdmi?

Since you have used the 6ft cable on laptop A and verified that there is nothing wrong with it, it is simply a matter of signal power. It may be that laptop A is not supplying the right amount of power for its signal to traverse the longer cable (more than 4 times longer than the short one).

In college, we learned that copper wires have internal resistances that reduces the amount of power passing through it. So the longer the wire, the greater the internal resistance, the more power needed for a signal to pass through. So if you haven't realized it yet, you cannot imagine the huge amount of power surging through those big long power supply lines... it can fry a human being in an instant of contact.

So basically, the power being supplied by your laptop A is not enough to traverse the longer HDMI cable. You can try a 12 or 15ft cable instead.

You might want to buy this to protect your laptop's screen:

watch the video: http://www.newegg.com/Product/Product.aspx?Item=N8...

Protect your screen from cracks, get a COOLER MASTER U2 Notebook Cooler w/c has dual purposes. Cool thing about it is, you can position the fans on the right spot for better ventialation.

When travelling, detach the easily detacheable dual fan, then use the aluminum frame as a protection for your laptop's screen when inside the bag. I got mine from MicroCenter.com for $15, 48% cheaper than the regular $25 tag (FRYS.com SKU#: 6344931).

click to buy: http://www.microcenter.com/single_product_results....

Additional info, read on:

I used to work for a big name computer company & usually received a lot of calls regarding battery issues.

A brand new computer's battery comes w/ a Standard 1yr Limited Warranty w/c means the expected life time of battery is only 1 year. Same thing goes for the charger.

So, if you don't know how to take care of it, it will die out on you sooner than than expected.

FYI: I always tell my customers, a laptop's battery is similar to a cell phone's. You charge it when it's depleted & you unplug the adapter when it is already fully charge (this will prevent the battery from getting overcharged & extend the life of the battery). So for less hassle, I always advice my customers to just remove the battery if they plan to use the computer for long hours straight (more than 1 hour) and just run it on AC power alone so as not to overcharge it & shorten the battery life.

ONLY USE THE BATTERY FOR PORTABILITY, if you're on a trip, at McDonalds or Starbucks.

If you're not after its portability, use it plugged into the wall socket all the time.

For chargers, make sure you don't stretch out the cable too much that the one by the power jack that you plug into the side of the computer gets bent. Make sure this part is always straight or else the copper wires inside will break & you'll have the problem of the charger not working anymore like what happened to some of my callers.