Speaker mic turned off - NEC Electra Elite DTU 16D-2 Corded Phone

You need to check your specs on the amp and preamp. There is a mismatch with impedance or you are overdriving the amp input and internal feedback circuit is trying to clamp it and causes that sound. It is known as motorboating.

get it away from the ext . speaker. They are cheap enough ,buy another one and see if it still squeals. If it does then you may have to jump the mic with resistors ,turn down your mic gain, check for talk back on rear where your pa. and external speaker hooks to inside the radio. If you see a resister connecting them then you have talk back . Mainly its a Keep the mic away from the speaker deal that makes them squeal. Try other cobra mics with the same pin out and see if it still happens . easy fix just have to be patient .

The mics are of two types: electrostatic(cheap and modern) and old-stiled "dynamic". Old souncards were automatically switching to the mics type. Modern soundcards have to be switched manually.
In "sound properties" you first must check in that mic is turned on, mic volume in max and in all menues avd buttons find something like "mic amplifier boost"and turn it on. It's only non-standart mic tuning option in standart systems. All other problems in defects. Soundcards can be verifyed by so:
(with maximal speaker and mic volume) many times plug in and plug out any reacheable mics and headphones to the mic connection nest (hole), and listen(or recording) resulting scratches. If scratches or other related sounds are abscend(only noise), soundcard is bad. The mic problem may be in "jack left-right interconnection". This useful thing may hang some improper cards. Also that cards often cannot work with dynamic type. And they very sensitive to a manufacturer, and model of mic.
Problem may be also in configuring multimode speaker nests in 5_1(7.1) cards like REALTEC - the mic nest may be switched to the speaker output mode. Open Realtec's control center(in control panel or quicklaunch icon) and check in mic nest to "mic mode" or switch mode from 5.1 to stereo speakers.

lower the mic volume or don't be so close to the your speakers when using the mic. or turn off your mic. thanks and have a nice day.

Make sure the speakers are forward of the mic's. If the speakers are in back the mic's will pick them up and feedback. Keep the mic's to the rear of the speakers and away by at least five feet.

If you can't meet this requirement, then you will need to use SPECIAL feedback suppression equipment.

Set up Audio

Laptop x webcam/mic x Vista x Yahoo Messenger
If you have an older OS than Vista you may have to access your hardware from the Contol Panel
I have used Yahoo Messenger as an example if you intend to use your mic in WLM or Skype, its a lot easier find 'Tools' and then 'Audio set up'

TEST SPEAKERS
Right click on speaker icon in System Tray
Select "Playback Devices"
The speaker icon ( checked as working) and volume level graph should be visible
Right click on the volume graph and click "Test"
Left hand speakers followed by right hand should be heard

SET DEFAULT & TEST MIC
Click "Recording" tab.
Set required mic as default - click on mic font to highlight and click "Properties"
In lower dropbox display "Use this device enable" click OK
Click "Levels" tab and ramp up sliders ( adjust to suit later)
Return to "Recording". Test mic by speaking and make sure volume graph displays

Restart computer

CONFIGURE TO MESSENGER

Open messenger - on top toolbar. Left click ( > ) Messenger > Preferences > Connection - Select 'no proxies' or 'connect direct to the internet' depending on the version of messenger you have
make sure your internet connection and country are correct in the lower two boxes > Apply > OK

Click ( > ) Messenger > Preferences > Calling and Audio
Set mic and speakers to show Default equipment
Run call up assistant to test audio equipment > Apply > OK

Typically you want to wear the mic 6 to 8 inches below your chin clipped to the lapel area. It seems in this case it has more to do with EQ and speaker placement. If you can stand behind the speakers while using the mic. The sound bouncing back and forth between the mic and the speaker is what causes feedback. Also try setting the mic channels EQ with the following settings.
Turn Lows down to about 7 to 9 O'clock
Play with Mids to match actual source, but never boost above 12 O'clock
Keep highs around 10 O'clock (boosting highs increses chances of feedback.) If to muddy sounding keep highs aroun 12 but not over.
Good Luck

Speakers are working OK otherwise?
Do you get sound from headphone jack?
It's probably some pot control not turned up.
Is MAIN OUT turned up
Are speakers connected to monitor out or main out.?
Is gain for mic turned up?
Is there a MAIN OUT switch (on/off)?
Is there a MUTE control on the board?

It sounds as though you are pointing the peavey at the band in a practice situation? If so make sure that each speaker is at about 60 degree angle to either side of the back of the mike (you facing the speakers), most mics reject feedback when the the user is directly in front of a monitor, but Beta 58s' tend to feedback more in that situation. Alternatively (if it is a practice room situation), why not place the speakers behind the band at 60 degrees each and turn to face the band.

The Board have three sound port one for rear one for front and one for mic plug in the mic pin into the mic port red colored.
Then go to the realtek control panel located in the taskbar like a red speaker open it and go to the I/O
options and the mic options turn on front mic.