My original post: https://bitcointalk.org/index.php?topic=482352.msg6077816#msg6077816

I have tried CPUminer, which works for a few minutes, after which, it won't accept shares. I left it running last night and checked it this morning. The graph at givemecoins.com which gives a minute/hour activity of the miner shows that I was accepting shares for 5min, and then it flat out bottom and never picks up anymore after the next 5Hrs.

The next 3hrs now after waking up, I have also tried using different USB2/3 ports, and have tried using my beefiest PC using cpuminer (I used my Core i5 laptop and Core i7 desktop) with similar results: 67Kh on BFGminer consistently, cgminer crash time and again (on all 3 PCs with Zadig WinUSB driver), have tried reassigning COM port and playing with baud rates. I am starting to think I got a lemon seed and this is very frustrating.