See Various simple rename presets, number 5: Make Safe Name.
If you had edited your earlier post to add another question, I would not have noticed it and given you an answer, since I had already read your post. That is one of the reasons why you can't edit your own posts in this part of the forum.
The trick to regexps is to learn the basics (which look daunting at first but are really pretty simple), and then tackle each problem by breaking things down into small parts that are easier to solve on their own.
If you want to learn, my post RegExp basics: Removing characters from start/end of names should be a decent place to start.
By the way, the regexps I gave before look a lot more complicated than usual because they have to deal with ( ) [ ] characters, which all have special meaning within regexps.