My dell laptop sleeps almost as soon as it is powered on. After such sleep, it doesn't respond to the power button, doesn't respond to anything at all. Sometimes, I'd have to wait for days before the laptop will respond, and then it will immediately sleep again.
I have changed CMOS battery, hard reset, everything I have read on the Internet still unsolved
I've had this same problem on the Dell XPS 13 (L321X), and I fixed it by unplugging the "sleep indicator" cable.
Here's what you do:
Follow the iFixit guide for replacing the battery on a Dell XPS 13 (L321X) (at this page) and just stop at Step 2. Basically you just need to open up the back cover and then disconnect the white ribbon cable, which controls the sleep indicator light. (As soon as I disconnected the white ribbon cable, the computer wake right up from sleep.) I also put a small piece of electrical tape over the end of the ribbon cable just to be safe. Put the back cover back on, and you shouldn't have this problem anymore.