everything fine and dandy until i sent in the laptop for warranty LCD screen replacement.

Laptop is 3 years old, Dell XPS 15 3200x1800, 4702HQ i7

Here are the issues and wondering if they're linked

1. noticed on 2 occasions plugging in didn't charge the battery

2. last night the screen came up with spots everywhere when CPU idle.

-when doing something the dots disappear (as simple as moving the cursor with trackpad = no spots)

- when plugged in the dots disappear

- when screen duplicated on external monitor (or extended), spots disappear

Made sure BIOS and GPU drivers (and all other drivers) up to date

I don't think it's the LCD screen ... something else ... 

Might try to revert back to pre-anniversary edition to rule out OS

Will try to get a pic later