Alright, so usually I know how to fix most system problems, but this one has confused the hell out of me. I am running W7 on my dual-core system, and recently it has started lagging a bit. I look at task manager, and csrss.exe sits at around 50% cpu usage (something that hasn't happened before). I looked around on google, and there are many suggestions that it has become infected, but neither NOD32 picked it up, nor did any of the suggested checks turn up anything. any help plz?