[Elecraft] "K3 VFO A not responding" message

[RLVZ at aol.com]

Hi Guys,
 
I've been a happy K3 owner for aprx. 3 years.  Regardless  which CPU I use, 
I've always had an occassional problem receiving the error  message "VFO A 
not responding".  When this happens  while "running" during a contest it 
presents a serious problem as the  computer and radio lock up for aprx. 30 
seconds.
 
During this 3 year span, I've operated with a dozen  different Windows XP 
and Windows 7 computers, always using N1MM Logging  Software.  I've operated 
from several different QTH's and have the  same problem.  I always connect 
via a Serial Port  regardless of which CPU I use and have not tried a USB  to 
Serial Adapter.  During the past few months, this problem has  really 
increased, such as: during last weekends CQWW  Test, I got the dreaded "VFO A not 
responding" message and computer lock-up  at least once every hour.  By the 
way, I do not have a 2nd  receiver in the K3 so I cannot say if I'd have 
the same problem with VFO  B.  
 
I'd be grateful for ideas on how to eliminate the "VFO A not  responding" 
problem.
 
Thanks & 73,
 
Dick- K9OM