hi im deffinetly not a pro, but work with msn messenger alot, so let me tell you what i know i myself connected to the router directly and everithibg works fine, you should check if you have some kind of firewall that blocks UDP. besides that as far as i know voice will work only if one person behind switch, and not both, so if you trying to communicate with someone behind switch, internet connection sharing or anything it will not work. well, thats all i can think of. o, yeah, here is another reason why it doesnt work, it may not feel like working (thats the reason it doesnt work on one of my work computers), so you may want to try windows messenger, or maybe even MSN 6 beta, that might fix the problem good luck