INFO function

=Info() can be used to get information about the location of the file, information about the OS, excel version, about the memory status etc....

Here are some examples:
=info("directory") Path of the current directory or folder.
=info("memavail") Amount of memory available, in bytes.
=info("memused") Amount of memory being used for data.
=info("numfile") Number of active worksheets in the open workbooks.
=info("origin") Absolute A1-style reference, as text, prepended with "$A:" for Lotus 1-2-3 release 3.x compatibility. Returns the cell reference of the top and leftmost cell visible in the window, based on the current scrolling position.
=info("osversion") Current operating system version, as text.
=info("recalc") Current recalculation mode; returns "Automatic" or "Manual".
=info("release") Version of Microsoft Excel, as text.
=info("system") Name of the operating environment:
=info("totmem") Total memory available, including memory already in use, in bytes.

Where Can it be used?
=info("directory") function can be used to get the path of the file in your reports.
=info("recalc") can be used to check whether the calculation status is 'Manual' or 'Automatic'.

Now there are other ways to get most of the above information, this formula is one more option that you have.

Some Text functions

We will see some Text functions which can be very useful:
1. TEXT() :
This functions formats a number and convert it to Text. For E.g., Cell A1 is having date 1/1/2009. We can convert this date to text in whatever format we like; e.g., TEXT(A1,"MMDDYYYY). The result will be 01012009. Likewise we can convert a number to text like 100 to 100.00 (Text(A1,"0.00"). Note that you may have to specify the decimals.
2. TRIM():
Trim function is used to remove extra spaces from text. Syntax: TRIM("Hello "). Result will be "Hello".
3. LEN():
LEN function is used to know the length of a text or character. It will count the spaces too.
4. UPPER():
This function is used to convert a text to UPPER case.
5. LOWER()
This function is used to convert a text to LOWER case.

When I open a workbook it prompts me to enable macros; although there are no macros in the file. Why?

Whenever Macros are recorded in a workbook, Modules get created. These modules house the VBA Codes. So whenever Excel detects any module in a workbook it prompts you to enable macros even though there might not be any macros in he file.
Example: Sometimes we try our hand on Macros and then later delete these macros. Even though there are no Macros, Excel gives an Enable Macros prompt on opening the file because the file still houses the Module(s) (including Class Module(s) if any) which have not been removed. So if you are wondering why this popup when there are no macros? All you have to do is go to the VBA Screen (Alt+F11) right click the Module(s) and delete them; this will get rid of the Enable Macros prompt.
Note : Some people get the impression that this popup appears for macros have been used on the workbook in past. However this is not true as running macros from personal.xls or an addin or any other file will neither create VBA code (in sheets or modules) nor will it create new modules. Hence mere running of macros ona file will not result in ‘Enable Macros prompt’ when you open them.

Phantom Links

What are phantom links?
A Phantom link is a link which does not exist and hence can not be updated. Most of the phantom links arise when someone sends you a workbook which is linked to other workbooks to which you do not have access. It's called a phantom link ‘cos the reference does not exist and hence can not be updated.
It will also arise when you change file name of one of the linked workbooks. The file which contained link can not find the old file name, making the link phantom. In such case excel prompts you to update the link.