The two main reasons I've seen HW errors accumulate are either having thread-concurrency set too low and driver issues.  With my 6990 I had to downgrade to older drivers / APP SDK because every hash was failing.

Roughly 1 BTC, though most of that is tied up in LTC and TRC.  This is after mining and trading for about a week. 

I haven't invested anything other than time and electricity.  My gaming rig (AMD 6990) was repurposed for mining, however.

Based on the evidence presented so far it looks like there may indeed have been a trojan included in one of the miner applications.  I haven't seen anything suspicious happening on my system and have been working through the released win32 binary in IDA pro.  That said, my personal investigation is far from over, so regardless of what precompiled binaries you download, be careful.  The same is true of anything, not just altcoins.

[EDIT] I was unclear.  I mean that I have not seen anything suspicious in the YaCoin application itself.  I have not investigated the miner apps at all.

Thank you for this.  I'm currently doing some development work, and this minimal implementation will go a long way.

I am an experienced freelance developer with 13 years work in systems administration.  I am willing to develop applications, games, BTC/altcoin utilities, and more and will accept payment in BTC or LTC.