I have installed ubuntu 11.10 on a windows 7 pc alongside windows 7. But after some days it has problem. I want to re-install it. Do i need to uninstall current ubuntu? Reply fast if you are sure!
You can install over the existing install without removing it beforehand.
Start the install, when you reach Allocate Drive Space section choose Something Else.
In the partition window you will see your ntfs partitions and linux ones.
Select the linux partition - pick Change from the options.
Select Ext4 as the Use As - select the format option.
In the mountpoint - select /
Close that window and then carry on.