Validate a folder path using regular expression

Use last link to see a nice graph of your RegEx.
I don't know what you expect to match with this RegEx, but it look very wrong.
You should improve your question and describe precisely what you want (and don't want) to match. By the way, the language you use matters too.

Just a few interesting links to help building and debugging RegEx.
Here is a link to RegEx documentation:
perlre - perldoc.perl.org[^]
Here is links to tools to help build RegEx and debug them:
.NET Regex Tester - Regex Storm[^]
Expresso Regular Expression Tool[^]
This one show you the RegEx as a nice graph which is really helpful to understand what is doing a RegEx:
Debuggex: Online visual regex tester. JavaScript, Python, and PCRE.[^]

srilekhamenon[^] wrote:

i had tried expression something like this
^(([a-zA-Z]:)|(\\{2}\w+)\$?)(\\(\w[\w].*))$ but this is allowing special characters

If you would like to check if path is correct (doesn't contain invalid characters, etc., use Path[^] class. See:
Path.GetInvalidFileNameChars Method (System.IO)[^]
Path.IsPathRooted Method (String) (System.IO)[^]