How do I disable the pop-up flash on Nikon D5000? Thanks

hi,
external flash can use.

Sounds like the flash tube is bad. Another possibility would be a bad flash capacitor or circuit. Has the camera been impacted - especially around the flash?
Another possibility is that the light tube that goes from the frame around the tube to the sensor further back in the flash base has come loose or impact has broken the frame.
Pop up the flash. Underneath there are two screws; remove the screws, push the flash back down and using a slim piece of metal pop off the flash cover. You can then see the tube and the light pipe (looks like a thick black wire) and the sensor located at the back on the right.
Be very careful. There can be over 300 volts across the flash tube - do not touch!!!

It screws in from the bottom of the top cover. You have to remove the bottom, back, and front covers, discharge the flash capacitor with the proper tool, unsolder and remove the top cover. and unsolder the dedicated contact pins from the top cover flex, plus any other things the top cover flex is connected to (usually the solenoid that controls the pop up of the flash) then you carefully pull the flex out of the way to reach the four screws that hold the hot shoe on.

hello try to change the cable that might helps please rate my comment thanks

Well I found the Vivitar 2000 auto in a thrift store, and it seems to work perfect with my Nikon D5000.

Hey check out this video. the solution to the d5000 is same. the hook is a bit different though on the right.

Assuming you have the Nikon variant of the flash, it should do anything the D5000 can handle. It won't work as a Commander, so if you need that functionality you'll have to get an SB-900 (or an SB-800 if you can find one).

Check out this video. The solution is similar to the d5000. I got mine resolved.

No. First the Canon 199 was designed for the Canon camera, and the electronics are very different in the Nikon. Two the 199 was designed for film and the digital metering is completely differnt for digital. Buy a Nikon flash.

The 550 FD came out before digitals. It is fully dedicated(FD) to a type of film camera. Usually this is noted on the back of the flash. CA or C for Canon, MI or MX for Minolta, Ne or NI for Nikon. If its the Nikon dedicated unit, it should not harm your camera, and will most likely work...as a manual flash. You will lose all the neat flash stuff that the D5000 can do.
I suggest you watch Ebay for a Sunpak PZ-30, PZ-40, or a Sigma 430 or 500. The Sigma EF 500 Super will do pretty much everything the top of the line Nikon Flash does, but you can buy it new for half the price of the Nikon unit. All flashes today are dedicated to a certain group of cameras by a certain manufacturer. For example: Canon EOS film cameras or Minolta manual focus cameras.
I suggest you get rid of the 550FD as it is designed for the pre-Autofocus cameras.
Avoid the Sunpak Auto 30DX, the 333, 383, 433, 444 and the PZ 4000/5000 as well as the MZ flashes. These were not designed for your new digital.
Metz also makes some very nice flashes, but they're kinda pricey.