That question is asked at least 4 times a month here.
Please do, at least, a minimal Google search before you post any question :
Here's the Google search. The first link returns the answer to your question.
http://www.google.com/search?hl=en&q="delete+a+file"+"c#+"asp.net"
Juan T. Llibre, asp.net MVP
asp.net faq :
http://asp.net.do/faq/
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http://asp.net.do/foros/
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