That cannot possibly work, since there are no Greek letters in Latin1. If you run this piece of code, you will see no Greek letters except for µ MICRO SIGN.
for i in range(256):
c = chr(i).decode('latin-1')
print c, unicodedata.name(c, "")
I'm not an expert on Windows, but my guess is that the data coming out of the clipboard could be using one of these encodings:
ISO-8859-7 # The code page used by some Greek versions of Windows.
I'd try ISO-8859-7 and UTF-16be first, like this:
data = win32clipboard.GetClipboardData()
data = data.decode('UTF-16BE')