here is my question: I've installed ubuntu in a partition of the same disk where it is windows 7. Now i've grub that allows me to choose between windows and ubuntu. I would like to replace this ubuntu version with another fresh one because i think it is too heavy for my hardware. I don't want to install just the lubuntu desktop but i would like to perform a fresh and complete install of Lubuntu instead. Will Lubuntu new installation replace the ubuntu without any problem? For example will i have to reconfigure grub or the new installation will manage it? Thank you in advance.
The new installation will take care of the grub entries. Make sure to install the bootloader in the MBR.
Just be careful while partitioning because if you have only a single
/ partition, you will lose all data that is present in your present home folder. just back it up and start off with Lubuntu installation.