Using laptop for playing music through an amp for dummies

Hello everyone,

I am new to this audio stuff and I have a couple of question I hope you can help me with. My computer is Lenovo Thinkpad X200 and I would like to connect it to my amplifier (Onkyo 508). However, it seems for me that my laptop does not have an optical output and neither does the ultrabase docking station. I heard that some computers have it integrated to 3.5mm headphone jack. How can I find whether this is the case with X200?

I guess that I can buy an external sound card and then use its optical output jack. If I do it this way, does it mean that my computer works only as a network hard drive and all the "musical work" is done by the DAC in the amplifier? So does it really matter what kind of (or how cheap a) external sound card I purchase, if in any case, it is just an "digital output provider"?

So basically, what kind of things should I consider in connecting my laptop to the amp?

Originally, the computer was connected analogically through the 3.5mm jack, but the problem was that there appeared some kind of noise. I guess it should disappear if I use digital output (and an optical cable). I noticed, though, that the noise disappears when I disconnect my external display (which is connected to the laptop by VGA), but that is not really an option, since I need it.

Yeah, I have 3.5mm connector, but when I use it I get extra noise, which disappears, though, if I disconnect my external display, but that is not really a solution.

Ok, sounds good.

Some of the sound cards are for 5.1 (or 7.1 etc.) audio and some only for two channels, so does this matter at all? Since the signal is going unprocessed to the receiver, I guess it shouldn't matter what are the specs of the sound card if you use the digital output?