Hi Jack Thanks for your help! That was the first thing I tried, I went through old soldering joints but without luck. Then I run a bit forward and removed the FTDI chip and replaced it with a new one (I used hot air gun). The PC can now see the Papilio via USB again! Now I am just afraid if I download my previous design again that will kill it... (I don't want to resolder it again) But I also believe that a design cannot kill the FTDI chip. It could kill the FPGA IO pins but not the FTDI... I am now simulating my design and verifying it one-by-one. Honestly I have an own made special wing with 2x 4464 DRAM chips (with Quickswitch bus transciever to do voltage translation on the data pins), VGA, PS2 key on it, something like the Arcade wing. I have tested the PS2 keyboard part and it was working fine, then I turned it off and the PC never recognized it again. I was wondering whether static electricity could kill it when I remove the USB connection. Thanks for your offer on helping with the board! I have just purchased a Papilio Pro also which is on the way still. I am working on something that I don't want to release at this stage, but will be released when it is working. Thanks Istvan