Error 500 after updating from 3.4.X to 3.4.8

[wlwanhk]

Dears,
I would like to update to the latest ver. of Joomla because of encountering some security issues. Besides that, everything runs smoothly.

Here's what I did:
Click the update button in backend > file and said "The Archive file is corrupted, truncated or archive parts are missing."

How to solve:
Edit the configuration.php, update the tmp_path location

Result:
The updating run and freeze when around 8x%, pop up with the same error msg as below:
The Archive file is corrupted, truncated or archive parts are missing)

I leave the page for a while, when try to login again, the [my domain]/administrator/ can't show and appear error code 500.

I'm new to the server setting and hope someone can give me a hand to fix it.
(some info fyr:
latest status @ joomla_update.php: Starting installation of new version.
server: iis 2008
php: 5.4.24
administrator.php permission: have the modify right already)

Thanks~

[itoctopus]

You can just download Joomla 3.4.8 and extract it onto the main folder of your current website. Make sure, of course, you backup your whole website before doing this (so that you can revert back in case something wrong happens).