long time lurker first post lol smth is choking my PC... loading screens take forever, textures pop in late, and a flight sim stutters constantly. task Manager:

Disk 0 (C:) Active time 100%
Not responding
100% disk, and teh response time numbers look scary. i suspect a cloud sync app, but Im not sure how to prove it.
i already restarted the PC and closed everything i could find in the system tray. disk usage dropped for a moment, then went straight back up as soon as teh game loaded a new area. seriously need help here 馃槶