Multiple file upload and view files in IE.

Hi...

I need a logic for uploading multiple files.

My Requirement is-
1. User must be able to upload multiple files at a time.

2. Files details - File Name, Extension, and File Size should be inserted in the database(sql server table) - DONE.

3.Files details are shown in the gridview - DONE.
There is a "VIEW FILE" link in the gridview.
On Clicking this link, the file should open in IE. How to open files in IE ??

4.Check whether the file is repeated while multiple uploading or not. If yes, it should give an error message.

5.Files are saved/uploaded in the folder  (Physical Path, in my case it is E:\UploadedFiles\).
From the front-end, I want to check whether the file exists in this path/location or not.
If yes, the link "VIEW FILES" must be enabled else if the file does not exists, this button "VIEW FILE" should not be enabled. - HOW TO DO THIS ??

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Please help.

Thanks a ton to all in advance....