A profile is a special script file which is run when PowerShell starts up. You can use these script files to store functions and variables that will be persistent.

You can see whether the various profile files exist by issuing the following command:

$profile | gm *Host* | % { $_.Name } | % { $p = @{}; $p.Name = $_ ;$p.Path = $profile.$_; $p.Exists=(Test-Path $profile.$_); New-Object PSObject -Property $p } | Format-Table –AutoSize

More info: Setting up a PowerShell Profile