Notice of DMCA removal from Google Search

So I just got a "Notice of DMCA removal from Google Search" because apparently my website was guilty of copyright infringement. Does anybody know how to get around this? If I just change my site to something else for a few days, fill out the removal form, and change it back after it's been re-listed will it be fine? Also what could have triggered this? It's been fine for months then suddenly I get this. Could it be because I added adsense to it?

Try a 301 redirect to a new domain

Ouch, that is the worst thing any webmaster could be hit by.
What content does your website have on it?

Does your website have copyrighted content on it or link to copyrighted information?

This is the most likely reason.

lanbo said:

Try a 301 redirect to a new domain

Click to expand...

That's what I figured would have to be done.

chummm said:

Ouch, that is the worst thing any webmaster could be hit by.
What content does your website have on it?

Click to expand...

manny521 said:

Does your website have copyrighted content on it or link to copyrighted information?

This is the most likely reason.

Click to expand...

I don't want to give away my niche but it's about free [keyword]. Maybe the company that owns the product didn't want me using it to make money? There's a bunch of other sites for the same keyword though and very few of them have got this (though there were a few others that did). Is it possible that a competitor could have reported me for it?