Hello and welcome to the forum,

I'll try to explain this as simple as I can, let me know if you find it too complicated.
Firstly,
Enter your computer BIOS.
To do this you'll need to press a certain key at startup.
It's usually F2 or Del or something, you'll see it onscreen at startup.

When you get into this you need to look around and find your Boot Device order.
You'll need to use the keyboard in the BIOS as the mouse won't work here.
It's location is different depending on the BIOS you have but it's usually easy to find.
When you have located this make sure it is set to boot from the Hard Drive first and not the CD Drive.
Then save the changes, exit and restart.

Post back and let us know if that solved your problem or if my explaination was too complicated