Win32's GetFullPathName and GetLongPathName will do that.
The former also converts the path to an absolute path.
The latter also expands short file names into long file names.
use Win32 qw( );
# Win32 doesn't export these, so we'll import them manually.
BEGIN {
no strict 'refs';
*$_ = \&{"Win32::$_"}
for qw( GetLongPathName GetFullPathName );
}
my $path = "\\DOCUMENTS AND SETTINGS";
# If you wish to keep relative paths relative:
print GetLongPathName($path);
# If you wish to make relative paths absolute:
print GetLongPathName(scalar(GetFullPathName($path)));
Note that Win32's GetCwd returns the path as provided to chdir.
Tested.