Here are the minimum specs for the C-130 for FSX:

MINIMUM SYSTEM REQUIREMENTS:

   * - PC with 1.5 GHz equivalent or higher processor
   * - 256 MB of system RAM
   * - 64 MB DirectX 9 compatible video card
   * - 500 Mb of free space on the MS FS hard drive
   * - Microsoft® Windows® XP SP2 or Vista
   * - Microsoft® Flight Simulator X SP2 or Flight Simulator X Acceleration.
   * - Internet access (for installation/ re-installation)

Please note, we are unable to support technical issues appeared on systems that do not conform to the minimum system requirements.

As you can see, you must have either FSX SP2 or FSX with Acceleration for it to work. So if you don't want to install SP2, you can't fly the C-130 Demo. :(

Mark