i rma'ed my 2100
just call them up, their number is on the warrenty paper that came in the box with your chip
they will ask you some questions as to what is wrong and what led up to the chips demise.
if you did not use the retail cooler, dont tell them.
if you did not use the thermal interface material, dont tell them
the use of any other cooler or themal paste voids the warenty so if you used them, dont tell them over the phone.
they will have you put them in a box, packaged real nice and send it to them. i sent mine fedex and got the new one in about 3 weeks.
hope that this helps.