You may have to replace your display, but first you should look at the Burnt Out or Stuck Pixels section of the HP 7 1800 troubleshooting page.

First, make sure your tablet is charged. If the device does not charge, try another charger. If this fails, the issue may be with the battery or the logic board. Try replacing the battery. If that does not work, you will have to replace the logic board. See HP 7 1800 troubleshooting for more information.

Make sure your speaker is connected correctly to the logic board. If it is not, then connect it properly and see if it works. If the speaker is connected and no sound is produced, then the problem lies in either the speaker being broken or the logic board not picking up the speaker as a device. First try replacing the speaker. If this fails, replace the logic board. See troubleshooting for more info.