I'm having a similar issue with a newly purchased inspiron 15 3565. A few additional details:
- Purchased a shade over 30 days ago - found issue and began troubleshooting too late - Dell refuses to take return
- Support and I have run diagnostics - no hardware issue - because my warranty [purchased Dell refurbished] does not cover software, support offers to assist for one-time payment of 40% of purchase price or software warranty purchase at ~90% purchase price - I raise this to say, I'm coming here having tried a number of other fixes.
- Found posts in community suggesting that BIOS driver update may be required. Diagnostics confirm that BIOS driver update available. Attempt install, but system gets hung up on restart - stalls before restart is complete.
Problems:
- System is very slow - this is why I began running diagnostics - heard that BIOS driver update may help
- System will not successfully go into sleep mode or restart - screen goes to black but hard drive is running. I have left it for hours, plugged in, only to return to have to hard boot to get system back on.
Any suggestions are appreciated and I will attempt. No externals [USB, printer, etc.] are attached. This is just as it was when I removed it from the box a couple weeks ago.
Thank you!