How to repair and recover corrupt MS excel file? I am unable to open corrupt MS Excel file due to virus infected, I have crucial Workbook sheet got lost, so how to get back corrupted MS Excel file. Please help me. 

Did you try to repair the file using Microsoft Excel? 
I attached you two links that explain how to do this:

• http://office.microsoft.com/en-us/excel-help/repairing-corrupted-files-in-excel-HA001034656.aspx
• http://www.wikihow.com/Recover-a-Corrupt-Excel-File
• http://softwaresolution.informer.com/Repair-Excel/ (Third party software for free)

My recommendation is to try before doing the send the file to another computer and try to open it there, so you'll know if the problem office software, or file.

Can you be more specific what type of virus/malware infected your computer?

if it's some sort of ransomeware then most probably only chance to recover your files are from your old backup. read this link.

Excel file can be repaired manually if it is less corrupted but Open and Repair program doesn't work if highly damaged due to corruptions. I searched for solutions to repair corrupt Excel file and found one solution which is full of information and provides a guaranteed solution. I am sharing this solution with all the users -Excel Repair Toolbox. Follow the exact steps given in this programm and you will be able to access the data.
http://www.excelrepairtoolbox.com/

• Marked as answer by DredSephy Tuesday, July 08, 2014 10:12 AM

Repair tool of MS Excel allows you to repair Excel files with the help of "Open and Repair" function. Get these steps to repair Excel File:

1. Open MS Excel application
2. Click on file menu and click open
3. Select your file from system directory
4. Click on the small arrow at the right of open button
5. Select open and repair option

Second option is to extract data into Word file, WordPad or Calc (OpenOffice). Try any of these. For further detail, read this post :- http://nalavadebela.wordpress.com/2014/03/14/repair-excel-file/

This software is more result-oriented and specially designed for recover and repair corrupt, damage, or virus affected excel files. It is also supports to recover corrupt, damage password protected excel files. For more details visit here :- http://www.recoverydeletedfiles.com/excel-file-recovery-tool.html

When an Excel file gets corrupt, don't give up hope. Using one of any recovery tricks described in the article, you may still be able to recover data from it.

10 ways to recover a corrupted Excel workbook

Best utility to resolve all the corruption issues of .XLS/.XLSX files and recover everything like chartsheets, charts, worksheets, cell comments, and other data in MS Excel new black file. This software works on each and every Excel version like that-: 97/2000/2002(XP)/2003/2007/2010 and 2013.

To download: http://www.softmagnat.com/excel-recovery.html

If you are searching best solution to open and repair corrupt ms excel file then i suggested to excel recovery tool www.repairexcelfile.com