CDBOOT: Cannot boot from CD: Error installing Windows 7

Hello,
I’m installing Windows 7 on my desktop computer. I’ve been using my desktop computer for about a year and half. I was using Windows XP before, until I decided to upgrade my OS to Windows 7. A problem occurred when I tried to run my computer with the Windows 7 installer inside the DVD drive. I get this error message and I can't even boot.
- CDBOOT: Cannot boot from CD – Code: 5
- Boot Failure from Previous Device..
- Boot Failure from Previous Device..
- Broadcom UNDI, PXE-2.1 (build 082) v1.0.3
- Copyright (C) 2000-2002 Broadcom Corporation
- Copyright (C) 2007-2000 Intel Corporation
- All rights reseved.
- PXE-E61: Media test failure, check cable
- PXE-M0F: Exiting Broadcom PXE ROM.
- Boot Failure
- Reboot and Select proper Boot device
- or Insert Boot Media in selected Boot device
- Press any key when ready
What would be the reason for this problem? I don’t think it’s the installer, because I just recently bought it and it is a legitimate copy of course.
Thanks in advance.
