The only way to check ur imei is call to their centre or email to them...

This year i called them once and they verbally confirmed that 1 + 1 is no more valid with sis start from this year.

I have experience bring my friend phone to warranty without receipt and that phone not under my nameand no issue until get the whole htc one x replacement set.

Maybe you can say is my luck but i just think this thread is outdated in terms of info wise.

Take a phone to htc for warranty is just the same when u take ur samsung phone for warranty.

The differentis how u check your warranty and if you dont have the receipt they will remark your set warranty start from the shipping date/purchase date as they said. (But is quite confusing though).

Anyway if anyone buying a 2nd hand set jut call to htc customer service..you get everything you wany and send an email for black n white proof.

and the registration webpage is down