Router, Isp or Os issues? Gaming Lag spikes?

First "bottleneck" that I see is 2GB ram... running Vista alone with only 2GB of ram is problematic at best let alone putting any gaming on top of that. If it is Vista 64 bit (and it probably is)...max it out at the 8GB it needs. Vista is a serious memory hog... if possible you should upgrade to Windows 7, it runs better on less memory.