I submitted a ticket to CS Support but it was rejected on the basis that it has already been answered on KB or this forum.  I searched the KB with every search term I could think of, couldn't find it, went through almost every catagory point by point couldn't find it.  I tried search terms "IRS", "IRS Present Position" and some others, no joy.
The problem is this:  after installing 4.3 after I go through all the alignment and NAV procedures and start the flight, the present position on the IRS never changes, neither in VC nor in 2-D modes.  The other functions such as track angle, wind, groundspeed work fine.  I did not have this problem with the original 757 and 4.2

Can anyone direct me to a posting that addresses and resolves this IRS problem?

Thanks in advance.