Windows 7 - Sound issues w/ Theatron Agrippa

well, hi..

i just returned home from a private LAN party only to find that my sound is screwed.

what happens is, that i'm getting frequent scratch-like white-noise-like peaks (dunno how to explain in english, sry) on certain frequencies. which appear to be mostly everything vocal and quite some mids. bass doesn't seem to be affected. then again, some mp3's e.g. work flawless, while others.. it sounds just like a very bad telephone connection with everything "rustling"...

i'm sure that it's nothing related to my boxes as i have already replaced them.

i was guessing that the cables weren't properly plugged in. but in such a case, there's so little free room - they're perfectly snugged into the ports.

so, next guess was that i accidently might have damaged the sound card by plugging in a "jack cable" (? in german "Klinkenkabel") in the wrong port.

can anyone tell me if this might cause hardware damage or can anyone provide other helpful informations?

i've been searching the forums + the net, but you know.. searching for "sound problems" brings up quite some results - and none were related to my issues.

thanks to everybody that bothers with this

regards

jan.