okay, if you checked everything and still got problem...
this how i install,
-extract 18禁ゲーム) [101029] [sprite] 恋と選挙とチョコレート 初回限定特装版 (iso+mds+rr3).rar
- mounting and install with blue icon setup (run as administrator)
- extract ksc_updater.zip to where you install
-extract つ (NoDVD EXE)(101029) 恋と選挙とチョコレート rev3.rar to where you install
- start with "start.exe"
- it ask serial number , open your serial.txt . copy paste....
-done . enjoy.