ubun2^beta

Recently upgraded from ubuntu 9.04 jaunty to 9.10 karmic koala. 9.10 ships with ext4 file system but i still notice that after the upgrade the partition still says as ext3. Looks like ext4 file system is more powerful and faster than ext3. Since i have already upgraded to 9.10, now how to change my partition from ext3 to ext4? Advance thanks for the help.

Recently bought a HP Pavilion a6720f 64bit desktop machine and it came with windows vista pre-installed. I created another partition and installed ubuntu jaunty 9.04 desktop edition (should have waited for 9.10 :) ) Everything works great except there is no sound. I am able to see the Volume Control and tried to turn on off but no sound at all.
 

Firefox 3.5 browser just got released  and i tried
sudo apt-get install firefox
and also
sudo apt-get install firefox-3.5
but no luck. Still i see only firefox 3.0 browser installed on my machine. 
Please help

My machine has windows vista with service pack 2 on it. I dont want to format or get rid of vista atleast for now. How to install ubuntu without disturbing my windows or in other words use both?

I logged in as the primary user registered while installing ubuntu 9.04. After than i goto System > Administration > Users and Groups window. But to my surprise all the buttons Add User is disabled. I am pretty sure that i'm the root user. Is there anything else i need to do to make it enable?

The default video player that ships with ubuntu doesn't play or support some of the video format because all i am hearing the sound and don't see any picture. Please help me with a nice video player for linux that supports most of the formats. appreciate your help

Commercial partition managers are expensive. I'm sure there must be some free good open source partition editors. Please suggest one.
I'm aware of the one that appears while installing ubuntu. But what i am looking is a bootable one than can be burned to a CD/DVD. Thanks

Windows local dns hosts file is found at c:\windows\system32\drivers\etc. Is there a similar hosts file in ubuntu / linux and where to find the same?

My friend says it is possible to run a windows application on ubuntu, but he doesn't know the details. Your help is appreciated.