I opened semicolon delimited txt file with this code below and long account number showed up as scientific notation after saving to excel regardless of formatting to text that c
In Excel numbers are limited to 15 digits of precision. Your example number is too large for Excel to represent accurately - that may explain the conversion to scientific notation.
You should import that column into Excel as Text, not Number: then you won't lose any precision.
EDIT: if you step through the "open from text" process while recording a macro you should get something like this:
Workbooks.OpenText Filename:= Filetxt, Origin:=xlWindows, _
StartRow:=1, DataType:=xlDelimited, TextQualifier:=xlDoubleQuote, _
ConsecutiveDelimiter:=False, Tab:=False, Semicolon:=True, Comma:=False _
, Space:=False, Other:=False, FieldInfo:=Array(Array(1, 5), Array(2, 1), _
Array(3, 2)), TrailingMinusNumbers:=True
There is a step in that process which allows you to select what type of data is in each column.
Your "FieldInfo" paramter is a bit off I think: you should have 3 columns, but you've tagged col2 as text...