Laptop switches to TV, to laptop, and back again every 5 sec.

I have hooked up my Dell Inspiron 15 (N5050) with Windows 7 Home Premium to my big screen TV. I use a VGA cable, a converter box, and a s-video cable. The TV receives the signal fine, but there’s a problem:

When I plug the VGA cable into the laptop, I get images on both screens (laptop and TV) for about 5 secs. Then, both screens go black and then I only get images on the laptop. Then, after 5 secs, the screen goes black and then I get images on both screen again....and so on. Because I only have 5 secs, I don't have time to make any changes unless I unplug the VGA cable.

Also, each time the screens switch (from 2 to 1 back to 2 to 1...) for five secs, I hear the sound that you hear when you plug in a thumbdrive. It’s as if I’m unplugging the VGA cable every 5 secs and plugging it back in.

Any ideas?

See if you've got a hotkey combo on the laptop that can control the display being used. Usually something like Fn+F3 or Fn+F4.

Also the display adaptor software may have some configuration settings to play around with to customize how it all works.

Sounds like the laptop is trying to achieve a resolution that the TV can understand but with that convertor in the way, is receiving mixed signals.

Try reading your TV's manual to see its recommended supported resolution and set this yourself in Windows by right-clicking on desktop and heading to Screen Resolution. Alternatively if the conversion box has an inbuilt interface for adjusting settings, then tell it to output whatever resolution your TV manual suggests.
One good way to test things to begin with is to set resolution to 800x600; all TVs will support this resolution (though it looks absolutely horrid on larger flatscreens) and it will be a quick method of determining if your setup is working to begin with.

Oxy - The OP opened this new thread on the same problem contained in this thread: Cannot connect laptop to TV
A similar answer was given there by Katherinez212. No word back on that one yet.

OP might just have forgotten about their previous post. It happens unless you bookmark any threads like this you make Not that I have an awful memory and have to compulsively bookmark any help thread I create lest I forget that I even asked for help to begin with.

We can only wait to see what new feedback we get.