#N/A Error

=iferror(vlookup(2, A1:B100, 2, False), "")

Your syntax looks a bit odd. Will you please attach a SMALL sample Excel workbook (10-20 rows of data is usually enough)? However, please give us an indication of the approximate number of rows of data you want the solution to work with (100, 1000, 100,000 or whatever). Please don't attach a picture of an Excel sheet (no-one will want to re-type all your stuff before starting).

1. It does NOT have to be your real sheet - mock up a SAMPLE if you need to. But not 1000's of rows!!! It makes manual checking so tedious. Whatever you do... make sure that all confidential information is removed first!!

2. Make sure that your sample data are truly REPRESENTATIVE of your real data. The use of unrepresentative data is very frustrating and can lead to long delays in reaching a solution.

3. Make sure that your desired solution is also shown (mock up the results manually).

4. Try to avoid using merged cells. They cause lots of problems!

Unfortunately the attachment icon doesn't work at the moment. So, to attach an Excel file you have to do the following: Just before posting, scroll down to Go Advanced and then scroll down to Manage Attachments. Now follow the instructions at the top of that screen.

If you are really using Excel 2003, you can use IF and ISERROR. If you have a newer version (2007+ I believe), you can use IFERROR.

Try something like this:

=IF(ISERROR(VLOOKUP(2,A1:A100,2,FALSE)),"",VLOOKUP(2,A1:A100,2,FALSE))

That being said, the VLOOKUP formula doesn't make sense. You are telling it that you want to look in the second column of a single column range... I would expect it to return a #REF! error.

Please post a sample sheet as requested earlier.

You appear to have a couple issues going on. From your post #1

Vlookup(2,A1:A100,2,False)

this is telling the vlookup to look for 2 in cells A1:A100 and return what is in column B (that is what the second 2 is for). The problem is that it has to be written TO INCLUDE column B or it will return #N/A. I didn't read through every response so you may have addressed that.
next (post #7) if you are getting a #name? error for the vlookup in your first part of the post it is not recognizing something in the formula and NOT interpreting it as a vlookup.
the vlookup with the 7 will return #N/A if 7 is not found in your column C.
As for the #Name code for the iferror, I believe Pepe answered that for you in post #5. IFERROR isn't recognized in excel 2003, you have to use if(iserror(...
to repeat what Glenn mentioned in post #3, an attachment (per his description) would go a long way toward getting you the help you need.