HELP ME PLEASE!! When I run windows 10 , I accidently didn't install bootcamp and now my pc can't even connect to wifi. what should I do?

When you still have OSX on the disk too, hopefully in it's own partition:

Hold the Alt(option) key while you start up. A bootmenu is produced, if OSX is there, choose it, then start up with it.

Remove the windows partition; start Bootcamp Assistant and then do everything to partition and install W10 again.