1 White and 3 amber flashes

A definitive answer requires you to provide the exact model number -- XPS 9333, 9560, etc.  That error can relate to a bad reserve (CMOS) battery, but by itself, that won't prevent powerup so there has to be another issue with the system.
Unplug the system, disconnect the main battery from the system and hold the power button for 30 sec.  Reseat (remove and replace) the memory module(s) if they're replaceable.

Then try powering up again.

Not sure if this is specific to your laptop model but just had a look at some LED error codes and from what it says it's giving a problem that there's no memory detected. (1 White 3 Amber). Suggesting that there may be a problem with either the motherboard or memory (3 Amber 1 White ) will indicate the CMOS battery being flat

Probably should start a new thread but my issue is closely related:    Installed a new battery two years ago and all worked fine.   The computer started running a little slow and I was due for an upgrade so bought a new one and saved the Dell 15-7569 for my wife to use.   It was not provided to her immediately, because she was hooked on the old one before it died.  I am trying to set the Dell up and the battery seemed dead, so the charger (Dell from orig purchase) was plugged in and the 1 white/ 3 amber flashing started.  The computer ran OK but only when plugged in.  The first time I started it, the bios came up with the "battery ? not recognized", which I thought was because it was low.  I then realized that it was not recognizing the battery, charger or "something", after going thru testing and BIOS checks.  Everytime it was started, the BIOS opened with the battery issue, with suggestion about bypassing in settings.   I did not seem to be able to bypass the BIOS interruption.   My next step was to remove the battery (lots of screws holding back cover) and after reinserting after seeing no swelling of battery, as it is fairly new, the computer booted directly to Windows, without the stop at the BIOS screen.   Assuming it was OK but the 1 white 3 amber still flashing and the computer will only run while plugged into the power supply.   I can find no way to determine if the battery itself has any power or what level it is at.   Is there a way to check the battery capacity or whether the battery is being charged while the Power Supply is connected?   Any suggestions appreciated.   Not sure that the "Stretchable" post that there could be motherboard or memory issues could even be solved by a user, especially one at my age (88), but thanks for any suggestions.

I have a Dell 3280 All-In-One - the diagnostics pass ok, machine boots, but power light button flashes 3 amber 1 White.  What is the fix for that?

@Zutella​ Replace the CMOS battery.

I experienced the same problem—one white blink followed by a three-blink orange error code—but it got back to working properly after I changed the CMOS.