For now leave the sound card out - no need to complicate things more with something not necessary to run the system. Personally when I'm troubleshooting hardware I take everything off except a hard drive, RAM chip and video card...you might want to do this too and also don't drive yourself nuts trying to troubleshoot what could ultimately end up being a loose cable somewhere, save yourself some hassle and disconnect everything you don't need to run the system, put your power supply on a UPS and check all your connections twice before you do anything else! You can always go back to working on other issues like the sound card once the system is stable again. Based on that error and what you've said here the problem sounds like memory to me. You're on the right track - you're answering your own question here. If you take the memory out and it works with no error then you can make an educated guess that the conflict is something to do with the memory. I would start by detaching all memory chips except one and then start adding them back one-by-one until your error pops up. When the error shows up you know more about where it is coming from. If it's when you put the fourth RAM chip in, for instance, then it's probably either that dimm slot or the RAM chip itself so try the same ram chip in slot 3 and see if the error pops up...if not it's probably the slot...this is just an example but you get the idea. Memory is one of those things I find very hard to troubleshoot because the same ram chip that works fine 3 times in a row is hard to pick out as a point of failure when it doesn't work the 4th time - I've had this happen many times...you just have to be a smart, thorough detective. I've found I have to go one chip at a time and one slot at a time with numerous reboots sometimes to identify a failing ram chip or slot. A failing slot can be equally frustrating and hard to identify. Good luck!