Freepbx calls being dropped or not audible

Hi all

I am hoping that soemone out there has experienced this before and had been able to fix it or otherwise know what I can do.  All help will greatly be appreciated.

We are running a freepbx (asterisk 2.8.1) system at the office, however we have been experiencing a lot of issues as described below:

  - Issues started with the asterisk server simply hanging eveyr now and then with no errors being logged.

   - This seemed to get better however then we had issues whereby calls being transferred to another extension via our switchboard would just be dropped.

   - We initially thought this to not be too much of an issue, however the problems have now started escalating over the last 4 days whereby all calls are either being dropped after a couple of seconds or while talking to a customer or staff member, one of the parties or both can suddenly not hear each other resulting in the phone having to be put down.

 This is causing a lot of headaches and causing us to lose customer confidence and money.

I would really appreciate any help on this as all the checks we have done so far has provided us with no clues as to what is happening.