hi.
i have win xp myself,but its playing up just now,so dont know how win 7 behaves with the sim.
but it sounds like one of two things.
1) its not been installed correctly,is it just the c130 or do you have any c130 add on packs. if you have add on packs then they have to be installed in the following order:-
1. file csc is the base C130 file
2. file csj is the C130J
3. file cst is the C130T
4. file cs? is the CL130 float version which i dont have
5. file csk is the KC130
6. file csw is the AC130
7. file cse is the C130 extra pack
installing in the wrong order will cause problems as discribed.

the 2nd thing that may have caused this is any antivirus program you might have,which may have to be disabled while you install the c130.
i had to reinstall everything on to another disc and i had to disable part of avast as it was seeing the c130 install as a virus.
hope the info helps get you up and flying this bird. i know shes one of my favourite aircraft.
alan.