Powershell Script to update shortcuts

Hi there, 

I'm new to powershell scripts and need to be able to update any shortcuts saved in either the start menu or desktop.

I don't mind whether the old shortcut is deleted and replaced with a new file or if the path within the shortcut is updated. 

I found a PS script that updates the path however it only checks the logged on users desktop - I need it to check the above areas for all users.

Any help/advice would be welcome - i'm also keen to learn PS scripting so if someone would be kind enough to break down the script into a step by step tutorial I appreciate it.

Thanks in advance