I recently had a new battery put into my 6 year old XPS. This new battery does not seem to hold charge. I shut it down at night with (for example) 70% left but on powering up in the morning it tells me I'm down to 7%. And before anybody asks, I know how to power down a laptop. The old battery definitely needed replacing - it had swollen up and was lifting the track pad (as well as just not working). Any ideas as to why a supposedly new battery would not be holding charge? It seems to work OK during the day when I'm using it.
I've gone into the BIOS (what an adventure!) but I get 'Settings', not 'System Setup'. Therefore I cannot find Windows so as to hold down the Windows key and type "R" and continue with your instructions. However, are you wanting to know that it's a XPS 15 9550?