Another even simpler way involves creating a bootable USB flash drive with a fully functional copy of Ubuntu installed.
when you land a working CD, pop it in your optical drive and reboot your rig.
On the top bar, click System>Administration>Startup Disk Creator.

see to it both are selected, and you’ll be given a few options before creating the disk.
Realize, youdon’t have toerase the drive.
Any data currently on it will be available in the main directory after Ubuntu does its thing.
That said, it’s probably best to backup anything of importance.
Once everything is set, click “Make Startup Disk” and find something to do for 30-60 minutes.