when a limited user tries to run a programme as Administrator, using RunAs 
from a desktop shortcut, the programme window opens, but the contents of the 
window are white, and no operations are possible except closing the window.
In another post on this subject it was suggested it was a Group Policy issue 
- but when I posted this question in the Group Policy group this cause was 
not thought probable. The issue was resolved for another user by stopping a 
process called topsis.exe but this is not running on my system.
I have checked that the secondary logon service is definitely running.  I 
also use a desktop with Windows XP SP2 and on this machine Runas works with 
no problem. As yet I haven't been able to find any differences in the setup 
between the two machines.
Very grateful for any suggestions.