Sometime back i bought a second PC to serve as my backup machine, but i've never managed to have it as i would like. Now i want to start over, but i've messed so much with it's disks that i'm kinda afraid to lose something on the way, thus this question.

Right now, I have a 1Tb disk partitioned like this (as per GParted):

• /dev/sda1 (ext4) 346.12Gb -> Is almost full, has an old install of Ubuntu 11.10. It no longer boots, ever since i installed Windows7 on /sda3. Everything that matters to me is tucked into /var/www/ all the rest can just go.

• /dev/sda2 (ext4) 196.45Gb -> has an old install of 12.04 and nothing important, it's pretty much empty and also doesn't boot.

• /dev/sda3 (ntfs) 377.97Gb -> is my boot partition with Windows 7, some important files and I'd like to keep it untouched.
• /dev/sda4 (extended) 10.97Gb -> was created when i first installed Ubuntu, i think.

In my ideal world, I'd like to safely reinstall Ubuntu from the 12.04 liveUSB and merge sda1 and sda2 without losing any files. Is that possible? How?