accents removed when reading from text file

[lplover2k]

i am reading a text file line by line like this

dim reader As StreamReader = New StreamReader("c:\myfile.txt")
Do While Not reader.EndOfStream
  msbox reader.readline
loop

the accents characters are removed..
e.g.

instead of displaying
"González"

it displays
"Gonzlez"

any idea why??