Excel Information
Microsoft Excel is a powerful tool used to create spreadsheets and analyse the information contained in them. Excel allows you to store and manipulate information particularly of numerical data using Formulas, Functions, and perform many calculations and create charts and graphs. Excel is often used as a Database tool as you can sort, filter and transform text. It is compatible with Access and you can export data to Access and visa versa. 
Excel is the dominant spreadsheet application around, it has been so since 1995. The first version of Excel for Windows was released in 1987 it was named Excel 2.0. Excel includes VBA a programming language. The file format used in Excel is XML and the newer Excel 2007 uses .xlsx but it is possible to save files with the older format in Excel 2007.
There are a number of other file formats in Excel 2007, that I will not go into here, depending on whether you're a programmer and develop with macros etc.
Excel was the first Spreadsheet Application to allow users to transform text functions, fonts, characters and cell appearance. 
Information Source: "Wikipedia"
Excel 2007 new icon
You can quickly select a range of cells by clicking on the first cell and then press down on the Shift key, whilst holding down the Shift key go to the end of the cell range and click on the last cell. Excel will select all of the cells in the range for you.
When you use the delete key to remove unwanted data in Excel, the formatting of the cell remains, to remove the formatting and have a new unformatted cell, click on Clear.