Start Process as normal user powershell

It depends on what the issue is. If you are not running under a user context at all, like under the SYSTEM account, then you might need to run as a particular user, which typically means specifying a username and password, which is often problematic.

If the issue is that you currently have admin rights, but need to run something without those admin rights, then this should be possible using PSExec or similar methods without needing a Username & Password.

psexec -accepteula -l <CMD>

-l Run process as limited user (strips the Administrators group and allows only privileges assigned to the Users group). On Windows Vista the process runs with Low Integrity.

It should be possible to call PSExec within PowerShell and have PSExec call the original application. It may also be possible to do this through PowerShell directly.

It may also be possible to do this with PSExec without needing a username / password to be entered by executing something within the session of the target user as long as they are already logged in.

psexec -accepteula -i <session> <CMD>

In my own scripts I use psexec in those situations.

You have to specify username and password for a different account as well as an executable which then runs as the specified user.

This is not pure PowerShell but good enough for me. It may be possible for a PowerShell script to do the same thing psexec does. But unless you find out, this should solve your problem.