I run windows 8.1 in my p.c
but I cannot access p.c settings.(change)
I google it but nothing seems to help.
Any ideas

Thanks in advance.

do you have a file called File Explorer at the bottom task screen... icon is a folder.... click on this is this what you want

or move your arrow all the way to the right... icons should pop up... bottom one is settings

Not sure what you want to do, but in addition to what Winfrey says, I Googled and found several things...

Settings in Windows 8

I open the settings menu in the sidebar, click "Change PC Settings" at the bottom, and nothing happens, it seems inaccessible.

Try this... go to the tiled side and start typing in PC settings. Some search results should show up on the right... try clicking on PC settings and see what happens.

I get error message:
C:\users\rova\AppData\LocalPackages\wi...\AAA-SettingsPageAppsSearch.settingscontent.ms
The remote procedure call failed.

P.S I cannot access blutooth and others.

Have you run your anti-virus and anti-malware software yet? If not, I'd suggest you do that right away. Something is amiss with your system.

EDIT: I've been digging around and I'm finding a lot on a corrupt registry for this error. Have you run a registry cleaner lately or been in the registry yourself?

The problem was that the p.c settings tile was missing.
I had to copy-paste the setting icon to file folder.
Now I can open it.

Thanks for your help.

Well, I'm sure glad that's all it was! However, I still find it strange... I don't have a PC Settings tile either. I only access it through the Charms bar.

Yes,now I can access it as before, through the Charms bar.
I think the problem started after a windows 8.1 up-date.