This is from CGI:
 TO force a flash install:
Please follow these steps to run a group update policy on any laptop or Desktop PC 
First Step: Click start > type ‘Powershell’ in search box > Choose ‘Powershell’ program.
Second Step: In the new window that appears type gpupdate /force > press Enter
Third Step: Window will display ‘Updating Policy…’After a few moments ‘Completed Successfully’ should appear.
Fourth Step: If prompted to log user out, choose No by pressing ‘N’ then Enter. Close Window.
Fifth Step: If ‘Could not be updated’ appears, there is an issue with network connection.