Update.
I’ve been installing OSes on HP 6735s for several years already.
There’s a strange bug (or feature?): I can hardly install anything from bootable media.
Often, it just doesn’t boot.
I have never successfully installed anything from my USB sticks on this laptop. I always used CD/DVD.
The only solution which works so far is:
- Make bootable CD
- Make option “Boot from CD” first in your boot list in BIOS
- Start booting without CD
- Press ESC and then F9, Boot Options screen will open
- Insert your CD into tray
- Select “Boot from Upgrade Bay”
- Enjoy!
Don’t ask me, why this works. It’s just pure magic by HP.
After installing ubuntu on your hp6735s laptop it’s quite good to execute the following commands:
<
ul>
sudo gedit /etc/modprobe.d/alsa-base.conf and add
options snd-hda-intel model=mobile
sudo gedit /etc/modprobe.d/options and add
options snd-hda-intel model=mobile
that’s if your sound isn’t working 
*will be updating this page with good stuff for ubuntu/hp6735s laptop