RE: Two Serious problems

Sergio -
Regarding your first problem: 
I'm a new Excel user but had a similar problem with my Mac.  After
im****ting 
data from multiple text do***ents to make a worksheet, the computer would 
slow way down. What solved the problem for me was deleting all the named 
ranges Excel had created when I im****ted the text.  Click on Insert - Name

and choose Define. In the Define Name window you will see the named ranges
in 
your worksheet. You can click on one and hit delete. I had so many that I 
found the following macro to delete all of them for me:

Sub NLFI_Delete_Range_Names()
'
' Delete all range names
'
Dim NameX As Name
For Each NameX In Names
ActiveWorkbook.Names(NameX.Name).Delete
Next NameX
End Sub

Hope this helps, or somone smarter posts a better answer.