I installed Ubuntu 12.04 LTS using the Windows installer (Wubi) yesterday. And then I tried to install Chrome, Flash player, etc., but nothing worked. Then I tried installing some random package using the Software Center (to see if it would work), and that didn't work either. Most of the times it shows updating cache but nothing happens thereafter. Sometimes I get a message saying that it failed to download repository (I don't know what this means) and telling me to check my Internet connection.
I am using my institutional LAN network with a proxy requiring authentication with a username and password. Firefox is working fine...!
I browsed the Internet for solutions and I tried many commands in the Terminal but nothing worked. Today I uninstalled and then freshly installed it again, and then the first thing I did is to ask this question here. So plz help me... give me a step by step procedure to conquer Ubuntu.