How to enter BIOS

When you are starting up you should see a message to hit F2 to enter Startup. That is actually the CMOS screen, commonly referred to as the BIOS screen, where you change settings that the BIOS uses. This is where you will find what you are looking for.

yup, hit F2 at the blue inspiron startup screen.

Thanks, but I still a problems. When I enter the BIOS I cant find the place that I declare the Com port to be infrared. I someone could tell me step by step what to do, that would be very nice. If it matters, I have BIOS A08

I believe you hit Alt+P to page through the BIOS to find the one you want.  It is listed somewhere on the screen when in the BIOS.