It should be simple to install a software which do not need to have a post on it.
Then why am I having this post? because it is not that easy for sql server 2008 Express, at least for me.
I download it from microsoft and double click to install it just like any other softwares I have used.
Then the installer tells me that I have to install .NET framework 2.0 SP2 first, fair enough.
I go to microsoft download page, download the SP2 installer, then install it.
I try to install Sql Server 2008 again, it is giving me the same message.
After searching on the web, the answer is that it actually needs .NET framework 3.5 SP1, so I download that and install it, reboot.
Then run Sql server installer again, it tells me that I need windows installer 4.5+, okay, go through all that again. Finally you will successfully install SQL server 2008 Express.
What an incredible installer! good job Microsoft.