I want to install .wsp but it gives an error saying that there is a farm feature in which need to be removed. how to Remove Farm Feature (Farm Level Feature) from Central Admin or trough Power-Shell ?
It might be because there is already a solution with the same name (i.e. it is already installed)
From PowerShell with the SharePoint snapin loaded, first run:
Get-SPSolution
This will list all the installed solutions. Look for the solution that has a matching name and verify that it is listed.
If you want to remove the existing solution, run the following:
Remove-SPSolution -Identity the_solution.wsp