i finally managed to get my hands on the fs1 P3OEM DVD. you can tell it's the right DVD if it has "CD-DVD-273-GPE" above the words "Bundled Software" on the face of the disc.
contrary to popular belief, it does work on non-P3 systems. you need to use compatibity mode on all the .exe's in the fs1 folder. i set mine to Windows 95 compatibility. everything in the fs1 p3oem folder is mostly the same as the retail version. a program called FSP3.exe is placed in the fs1 folder. it is that .exe that provides the afterburner trails and planets in the background. you also cannot use the 1.06EAX patch even though 1.06 is the version that is installed (on the bottom right, in the main hall, it states, "v1.06 (Pentium III)" as opposed to a fully patched retail version which reads "v1.06 3DNow! EAX"). the other thing that is different is the root.vp. it includes the planet pics for the backgrounds in some levels and a few different trail effects for some of the missles.
one last thing, you can install "Silent Threat" with the fs1 P3OEM DVD, but it's quite a process. here are the steps:
1. look for the registry key "FreespaceP3OEM". the path is: HKEY_LOCAL_MACHINE/SOFTWARE/Volition/FreespaceP3OEM
2. rename "FreespaceP3OEM" to "Freespace" (do not put the quotation marks)
3. make a copy of Freespace.exe, FS.exe, FSP3.exe, FRED.exe, and the root.vp and put the copies into a separate folder or onto your desktop.
4. run the Silent Threat installer.
5. run the 1.06 patch
6. run the 1.06EAX patch
7. place the Freespace.exe, FS.exe, FSP3.exe, FRED.exe, and root.vp that you placed in a separate folder (or desktop) back into the Freespace folder.
8. go back into the registry and rename "Freespace" to "FreespaceP3OEM" (do not put the quotation marks)
9. extract the ships.tbl from the mdisk.vp
10. open the ships.tbl and add these lines after the line $Score on all ships that can use afterburners:
$Etrail: 100
$EtrailAB: 100
(you may not want to put these lines in the new ships that ST introduces due to possible game instability)
11. create a Tables folder and place the newly edited ships.tbl into it.
12. place the Tables folder into the Data folder.
13. have fun!
i personally would not go through this much trouble since Silent Threat sucks IMHO.
Cheers!