If it is the computer causing the static, this would fix it. But if it is interference from some computer components, then you would also hear it when nothing is playing at all.
Just to make sure though, have you tried the he-400 with any other devices? Or any other headphones with this receiver/PC combo? It could possibly just be part of the recording and you didn't notice it before, as the HE-400's are really revealing when it comes to that kind of stuff.
EDIT: Also, what kind of soundcard do you have?
Yes I have also tried it with my HD650s and they also picked up on the static background noise when plugged into the receiver/PC combo. I have also tried this with a Little Dot MkII amplifier/PC and there has been static but it is very minimal and relatively more quiet. Comparing the little dot static vs the marantz, the receiver combo makes the static definitely more apparent.
You do bring up some good points. These could all be a combination of the computer components, songs and receiver. As for sound card, I am using just the stock one that is in my Dell PC. It is about a year and a half old.