high-pitched ringing is killing me.

OK you guys promise not to laugh at me.  If my guitar is the cause of my issue, it'll just speed up the rate at which I save money to replace it, but it's a pretty "beginner" instrument. 

I'm recording a sustained chorded guitar part, nice and easy type of supporting sound. It sounds fine when I record it clean, but sending it into Guitar Rig 4 even with no amps or cabs I can hear a harsh high-pitched ringing tone on top.  I'm recording using an M-Audio Fast Track Mk II and a Squier Affinity strat using Dean Markley Blue Steel strings.  The Squier is my first electric, I got it for almost nothing.  I normally play on a Yamaha FGX series acoustic.  Anyway, the ringing is killing me because I haven't found the right EQ high-pass cut to slice it out without killing the sound of an already low-end instrument.  Any suggestions?  I can upload some WAVs with and without processing if you'd like. 

do I want the EQ before or after the amp sim?  Does it matter?     

Well a fresh set of strings seems to have cured it.  Can't believe I didn't think of that before.  Now it's time to re-record.

Thanks for the help marcos, I spent a little time trying to figure it out and thought that since the strings were right around 3 months old it might be time to just put on a new set. 

Your signal maybe too hot! Try lowering the input level and see how that goes.

I think -12 should be a good level for tracking guitar which then allows plenty of scope for processing.