My LCX25C doesn't have sound anymore. I can just barely hear the beeps but turning the volume up doesn't do any good.

I will likely need repair which isn't likely due to age of this phone.

Reinstall drivers for sound. then the volume control(mixer) will be put in the tray.

maybe by mistake you reduce the volume on the iphone.

try the following during a call press on the right control up volume to see if that improve your sound.

if that doesn't work you should go to an apple store or your cell provider.

If you are using a cable box or other device upstream, look into it's volume. Typically source units would like to be 30 to to% volume, with the tv or stereo being the final control. What happens is the source volume gets turned too low, and then the final unit (tv or stereo) has to have so much volume to hear anything, distortion and poor sound result. Start with both midway and you should be good to go.
This presumes that you toggled any buttons that said mute or attenuate...

had the same problem the hinge used in this model is causing this it get worn out quickly ,i had to replace it thrice within nine months......even pcb was replaced.now having problem with sys port ,i

y is it that when some one call me i cant hear them in the earpiece i only can hear them in my phone

thebuzzer of your phone is defected, replace itand replace also the earpiece 

Menu
Settings
Sounds
Volume

then select vol for :

Master Volume / Earpiece / Key Beep / Speaker Phone

Sounds like your battery is dying and the unit is saving energy.

the phone sux