I tried alot , Can't install kde on my pc

You will have to be more precise:
Which Linux distribution and which exact Plasma version is this about?
Is your PC something unusual? A little more information about the hardware would be useful.

Before the first step, make sure all your home files (documents etc) are backed up. Then if it all goes wrong it's not the end of the world. You managed to get on this forum so you have more than enough skills to get Neon and KDE up and running. Take your time, don't just use the first reply or advice you see, check for similar answers.

You said KDE do you mean Neon or are you trying to install K desktop environment on top of another distro. The safest bet is to clean install Neon, if you are using windows, you will be guided on how to dual boot during installation. If you have problems, abort before you commit, check out the forum and if necessary ask questions. Every step you make even if you have to abort, is learning and makes it easier the next time round.

Persist with it, it is worth it.

Thanks alot for your comment

Plasma version : neon-user-20200507-1116

and i tried to install it with windows 7 64 bit and did what in this video

https://www.youtube.com/watch?v=4bBZjxjNqAU

eslamtk wrote:Thanks alot for your comment

Plasma version : neon-user-20200507-1116

and i tried to install it with windows 7 64 bit and did what in this video

https://www.youtube.com/watch?v=4bBZjxjNqAU

The iso may still be broken
see viewtopic.php?f=309&t=165922

The installation problem may be a issue to do with wireless (which has happened before).

I did a new install last week using the 7th May ISO snapshot and it installed fine. I used the same ISO to install on a laptop yesterday and it failed - similar error message to other posters. The only difference is that my install last week was on a desktop p/c connected with a network cable.

Installing seamlessly in UEFI, MBR Problem.