|" vol does not mute & it does not go up &down."|
You should be able to do both of those things even if the speakers in the monitor don't work.
Do you have the audio plug for the speakers on the monitor plugged into the green audio port on the computer ?
Have you tried other amplified speakers in the green audio port ?
Go to Device Manager.
RIGHT click on My Computer - Properties - Hardware - Device Manager.
Does it show a problem with the audio adapter ?
A yellow ! ?
A red X ?
If there is no problem shown in Device Manager for the sound adapter, and if other amplified speakers work in the green audio jack.....
The F1723 LCD Monitor has an audio amplifier inside the monitor for the speakers.
Apparently sometimes electrolytic capacitors inside the monitor on it's boards are known to fail, and in that case, the monitor may not be able to produce sound from it's speakers, or may not be able to produce video, or both.
E.g. see this
HP F1723 LCD Monitor - How To Repair No Power
If you replace the defective capacitor(s), or have someone replace them for you, the sound will probably work fine
User's Guide for some HP monitors including F1723
Click on the floppy icon at the left end of the top bar to save the manual to your computer