Harry - here's my run down when ever I try to walk someone through an install;
You say you have a partition spare for it, that's fine. So we start the install, we follow the options through to the stage where you have a choice of installing completely or alongside Windows. At this stage you have a third option - Something Else.
I always chose Something Else. It is not as ominous as it sound.
Once you choose this you are presented with the GParted screen. Nothing to be afraid of here, just follow instructions;
click the partition you want to install Linux onto. Make sure you delete it. this will take it back to scratch.
Now click (or right-click) on the Free space and make sure you create an Ext4 partition in the Free space and select / from the drop down list and make sure that the size in KB will leave twice the amount of RAM your machine has, this will be used for the SWAP area. (I have a feeling that the SWAP area may be getting missed). Anyways, I like to have twice the amount of machine RAM for the SWAP area size. I have never had problems using this amount.
Now when you click OK the program should create your Linux Root partition which will contain all the paths for your system files once the install continues.
Now we have to create the SWAP area. Click or Right-click on the small Free space that you have left and select SWAP from the pull down list and click OK. This should bring you back once again to the partitions list.
If all looks ok you will have your Windows partition, your Linux / or Root partition and your Swap area. Sometimes you might have a tiny bit of hard disk left - ignore it if you have.
Now if it is all as I have said, click ok and follow the prompts. If it doesn't look right you can go back and try again just make sure you don't click OK at this stage if things don't look right.
So off we go if all is well and like Moebius said sometimes depending upon your CD/DVD drive you will have to press Enter after you have ejected the start-up disk. I have found it doesn't really matter if you hit the PC power button but, hitting Enter usually breaks the programming loop and restarts the machine.
By the way, I have found that during install on older, slower machines it is not uncommon to have a blank screen for around 40 minutes to one hour while a main part of the system installs. this would seem to be an install bug as there should be something on the screen to indicate that the system is still installing. If you feel that it is this point you get to then have a little more patience and let it go for a while longer. Have supper watch telly, etc.
I hope I have helped.
Let us know how you get on...