Sound card/5.1 surround sound not getting along

Hey guys, newbie here hopefully what I'm asking isn't a dumb question...

So a few months back I purchased a new tv and home theater system. The home theater I purchased is the 5.1 BD-1250 blu ray home theater. Anyway I hooked up my PC to my new tv as well. To make the sound come out of the 5.1 speakers I plugged in a headphone jack/rca cable to the receiver to make it work, which it did, but only 2 speakers out of the 5 worked (sub worked as well)

The ones that worked were the 2 fronts and woofer, the 2 rears and the center speaker did not.

I have a basic sound card in the system, so I purchased the sound blaster x fi extreme (which has optical output slot). I plugged in the optical into the optical 2 of the receiver and it still doesn't work, only 2 + the woofer works, nothing else, am I doing something wrong or was I misinformed that a sound card with optical out should do the trick?

Also is there such thing as a cable that has all the pc speaker connections into regular speaker connections? That way I can just plug it into the sound card and plug it into the audio of the blu ray home theater, help me guys, I'm desperate, thanks.

Long story short I want my 5.1 to work through my pc as well, I have a bunch of songs and movies I'd love to get the full benefits of these speakers, what needs to be done?

The headphone jack you speak of is known as a stereo minijack (3.5mm) cable. Going by the name alone, it obviously is only going to carry the signal of 2 discrete speakers.

Optical output is capable of carrying a limited bandwidth signal. It can either carry 2 channel stereo or a compressed signal such as Dolby Digital or DTS.

If you have a movie encoded in Dolby Digital or DTS, it (should) play back in 5.1. If that's not working, I recommend downloading AC3 Filter and using Media Player Classic - Home Cinema.

What kind of songs are these? If they are encoded into DTS, a regular movie player should work (WinDVD, CyberDVD). If they are DVD-A, Creative comes with a DVD-A playback program with your driver suite.

Samsung's website failed to download the user's manual for your system, so I can't say exactly what to do, but the specs say you have Dolby Pro Logic II, so you might be able to set your DVD player to upmix your stereo input to 5.1. Look at your manual, or monkey with the menus. If that works, you will be getting phoney-baloney surround with a stereo input, and true surround from DVDs and anything else encoded in Dolby Digital or DTS. I don't think that any YouTube content is in 5.1 yet, and precious little else online is, either. (Your mp3s are in vanilla stereo, which your HT-BD1250T is smart enough to make into 2.1 all by itself, I'm guessing.) Your Sound Blaster has X-Fi CMSS-3D Virtual, too, which should also do the trick.

Going by the scanty information I was able to glean from the Samsung pages whipped up by the marketing department without reference to the technical department, you don't have separate discrete inputs for the audio channels. Use an optical (TOSLINK) cable from the PC to the HT-BD1250T.