How to replace by html content in proper format and line break <br> are not working

how to replace by html content in Normal Format and
should be replace with new line in the same content, when i was placing content in textbox it is appear in the paragrah line rather than proper format line breaks are missing
I am using the regex expression
System.Text.RegularExpressions.Regex.Replace(Input String name,"<[^>]*>","")

can any one help me ??