There seems to be two working solutions to AutoCAD LT 2014 flickering. One is to use a file from a previous version and the other which is far simpler to install is to use a registry patch.
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Autodesk\AutoCAD LT\R20\ACADLT-D001\Variables\AECPSDAUTOATTACH] @=”0″ “StorageType”=dword:00000003 “SecondaryType”=dword:00000001 “LowerBound”=dword:00000000 “UpperBound”=dword:00000001 “PrimaryType”=dword:0000138b
Copy and paste the above into a text file. Rename it to autocadlt2014regpatch.reg (named only for ease of finding, the .reg is the important bit) and double click to install on affected machines. I have found that whilst this file can be stored in a server folder for ease of access, installing from the server is not possible and Windows 7 throws out an error. Just copy to desktop and install each time.