Hi,
A 6 beep error code is a video subsystem failure on the motherboard.
Here's a [https://www.youtube.com/watch?v=MBqq-7tYiIw|solution] that ''might'' work, but maybe not, you can only try. If not you will need the schematics for the motherboard to find out what's happened or you have to replace the motherboard.
Here's the [https://dl.dell.com/manuals/all-products/esuprt_laptop/esuprt_inspiron_laptop/inspiron-15-3542-laptop_owner's%20manual_en-us.pdf|owner manual] for the laptop, from this Dell support [https://www.dell.com/support/home/en-au/product-support/product/inspiron-15-3542-laptop/docs|webpage] for the laptop which may help as it shows how to access the motherboard etc.