Instead of simply opening the file, use the Data>Text from File method to import the data. For column 4, specify 'Text' during the import. For columns 1-3, you should be able to get the formats you require by applying custom cell formats after importing the data.

For column 1, use: 00000
For column 2, use: DD/MM/YYYY HH:mm:ss or MM/DD/YYYY HH:mm:ss
For column 3, use: 00000-0000, though I do know what you mean by 'ignore 2-digit blank spaces'

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]