Rm1000 possible issue?

Basically I've been having shut down issues on and off ever since around the time i upgraded to win10. Programs apps etc close, screen goes black as normal but mb and fans are still powered! I've tried leaving it but always ends with me having to hold power button to force turn off which i'm not keen on doing. Ive tried fresh installs of win10, checking for errors, troubleshooting via settings but it still pops up now and again. Even on a my new system it happens and the only parts that were reused were the RM1000 PSU and Samsung SSD.

This may be unrelated but a support guy at scan (where i bought MB/cpu bundle) mentioned it could be a faulty PSU as the cause.

If anyone else has had similar issues I'd like to know as I'm at a loss.