ok ive down loaded this ( USVIPER.zip here. ---> http://www.simviation.com/fs2004military2.htm) unziped to a temp. file, then copied and pasted to FSX\SimObjects\airplanes is their anything else that im missing to do......
Read my previous instructions carefully. Extract the zipfile to a temp folder & look for a folder inside it named VIPER. Paste the VIPER folder into FSX\SimObjects\airplanes.
If you do that it should be listed on the FSX selection menu.






 Glad you fixed it.
 Glad you fixed it.