Функции для получения папок - GetWindowsDirectoryP, GetUserProfile, GetUserDesktop

function GetWindowsDirectoryP: string;
begin
    SetLength(Result, MAX_PATH);
    SetLength(Result, GetWindowsDirectory(@Result[1], Length(Result)));
end;

unit Winapi.ShlObj;
function GetUserProfile: string;
var buffer: array[0..MAX_PATH] of Char;
begin
    Result := '';
    if Succeeded( SHGetFolderPath(0, CSIDL_PROFILE, 0, 0, buffer)) then
        Result := StrPas(buffer);
end;

unit Winapi.ShlObj;
function GetUserDesktop: string;
var buffer: array[0..MAX_PATH] of Char;
begin
    Result := '';
    if Succeeded( SHGetFolderPath(0, CSIDL_DESKTOP, 0, 0, buffer)) then
        Result := StrPas(buffer);
end;