Although Scientific Linux 4.8 is not the newest version of Scientific Linux, I'd like to introduce how to install it and to have a dual-system machine since STAR-CD 3.15 need an old version and Scientific Linux 4.8 is appropriate. Maybe someone will think it's better to use VirtualBox making a virtual Linux on Windows, But I guess that's not a good idea for people who need a large scale computation because a host system need resources to operate.
The first thing is to download the Scientific Linux 4.8 and burn a DVD (I think you have a DVD driver. If you have only CD driver, please download the CD version.) If you want to install it with USB disk or hard disk, I will introduce it later.
Preparation works:
1) move you data on the last one or two partitions to your previous partitions, and keep a least 20GB free spaces for installing Linux. (Although the Linux need only a smaller space, I guess you have a large hard disk for computation. The space is able to expand.)
2) reboot your system, and set the first boot driver is CD/DVD in BIOS, then save and reboot.
Installation procedures are the same as common Linux installation, please refer to other websites.
Reboot the system, and choose Scientific Linux to start.
You need to turn off automatically upgrade to avoid that new version of softwares crashing STAR-CD running.
After installing STAR-CD, you should edit /etc/X11/xorg.conf and add the line into the "Screen" section in order to avoid shading window projection:
Option "backingstore" true
then download openmotif-2.1.3 and install it.
Once you set the license file correctly, you could run STAR-CD.