To remove empty comments form Visual Studio 2012 use this regular expression:

^(?([^\r\n])\s)*//\r?$

and replace all the matches with nothing. Just make sure you are only searching in *.cs files. Because this can mess up other files, like JavaScript

Apparently whitespace is matched by (?([^\r\n])\s) in VS search and replace tool. While \s is a white space including new line and carriage return character

Reference to Visual Studio 2012 regular expression search is here: http://msdn.microsoft.com/en-us/library/2k3te2cs.aspx

Sometimes you would like to check passwords to be conformant with some rules. At least one digit, one letter is a common one. Here is the regexp for this:

(?=.*?[0-9])(?=.*?[A-Za-z]).+

Allows special characters and makes sure at least one number and one letter.

Update:

(?=.*?[0-9])(?=.*?[A-Za-z])(?=.*[^0-9A-Za-z]).+

Demands at least one letter, one digit and one special-character. The first one does not demand special chars, only allows them.