Read Excel file without office installed on server

just rename the *.xlsx file to a *.zip file and open it ;)
i guess this archive contains *.xml files.

Till Office 2003, Microsoft office documents where following the Binary format and you would need Office Interop to talk to Microsoft Office documents. But, this dramatically changed in Office 2007 forward. Microsoft follows the Open XML formats (of course, the XML tags are bit specific to Microsoft documents), but you can read all Excel, Word, Powerpoint files as plain XML documents like shown below:

<?xml version="1.0"?>
<w:wordDocument xmlns:w="http://schemas.microsoft.com/office/word/2003/wordml">
    <w:body>
        <w:p>
        </w:p>
    </w:body>
</w:wordDocument>

All you need to do is open these files using the Packaging interface which is part of .NET framework 2.0 and start reading the XML Parts using the Open XML standards.

Please refer to http://msdn.microsoft.com/en-us/library/bb456488.aspx[

Getting started with the Open XML SDK 2.5 for Office

] to have a jump start on this.

Of course you can!
Just download the introp library's here.
Download Visual Studio 2010 Tools for Office Runtime from Official Microsoft Download Center[^]