title: Batch rename - remove parentheses and whitespace and have leading zero
body: <p>so I know there are like a million similar questions (but sadly not quite the same, as always), but since I'm fairly new to Powershell and have real trouble with its syntax I hope someone is willing to help me out</p>
  
  <p>I already prepared the files I have with the explorer batch rename:</p>
  
  <pre>Name
  ----
  #20AR (1).doc
  #20AR (2).doc
  ...
  #20AR (10).doc
  #20AR (11).doc</pre>
  
  <p>Now, all I want is for the filenames to look like this:</p>
  
  <pre>#20AR01.doc
  ...
  #20AR10.doc</pre>
  
  <p>So I just want to have leading zeros, for the one digit numbers, and get rid of the parenthesis and the white space (the syntax provided in one SO answer sadly didn't work for me).</p>