Hi Guys, I'm having a weird issue with my OS. About 10 minutes after booting up then at random intervals after that, the CPU usage on one of my cores jumps to 100% and the desktop slows to a stuttering halt while the other 3 cores remain below 20%. I'm trying to figure out the issue and see if it's a program causing it, but I can't pin it down to anything. I'm using Process Explorer to look at everything that's running, but I don;t see anything out of the ordinary. I notice that 'Interrupts' jumps up to about 35% from an average of 0.5%, but I can't be certain as PE only shows the overall usage (averaged across 4 cores). I also notice that dwm (desktop window manager) spikes to around 25% at this time. Does anyone know any software that can analyze each processes cpu usage on a per-core basis so I can try to narrow the problem down? Or, I anyone else has experienced a similar issue, what steps did you take to resolve it? I have tried system restore, which rolled back my config to 2 days ago when I wasn't having this issue. I notice, that even though I haven't got WU to automatically install, when I restart after install The system updates! I've looked at the update history and nothing shows since February (the last time i used WU. I'm thinking this could be office 365 though.