It definitely sounds like a profile issue to me. I found an article(a) that talks about a similar problem caused by Powershell version 1 beta being installed at one time.
I would look through each of the files in the profile chain to see which one is remapping those aliases on you. You could then rename the profile file to test if it was the problem. I am not exactly sure how you are starting Powershell, but if SQL Server is starting Powershell, you will want to look at it's user account's profile.
This should do it...
notepad '$env:UserProfile\My Documents\WindowsPowerShell\profile.ps1'
notepad '$env:UserProfile\My Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1'
(a) Profile.msh possible errors:
If you load the profile.msh file, and
you have previously installed an
earlier version of Monad, then on
startup you may see a series of errors
set-alias : The AllScope option cannot
be removed from the alias 'cat'. At
C:\Documents and Settings\All
+ set-alias <<<< cat get-content
To fix this, either delete the file
named ("C:\Documents and Settings\All
this example), or remove all the
"set-alias" lines from it. Aliases
defined in profile.msh in earlier
versions of Monad are now defined
internally by Monad before the profile
is run; therefore, the definitions in
profile.msh will generate an error
attempting to redefine the alias.