so far no one helped me understand the difference
![Sad](https://bitcointalk.org/Smileys/default/sad.gif)
With the installer version, the program will be installed on your pc (by default in C:\Program Files (x86)\Electrum), and the program will create a data dir on your pc (by default in \Users\YourUserName\AppData\Roaming\Local\Electrum) to store your wallet file and a few other files.
With the standalone version, the program will not be installed on your pc, but the program will still create a data dir on your pc (by default in \Users\YourUserName\AppData\Roaming\Local\Electrum).
With the portable version, the program will not be installed on your pc, and the program will create the data dir in the same place you put your electrum-1.9.8-portable.exe.