Hello Wrongway and thank you for joining AVADirect forums!
Typically, when you see a flashing underscore symbol, the BIOS system is stuck on initializing a particular component. Most commonly, this component is your operating system hard disk drive. If it's missing, defective or has a corrupted boot record, the computer cannot find the operating system to boot into.
You've mentioned that the notebook doesn't boot from CD. What kind of a CD were you using to boot from? If you're using an operating system CD like Windows 7, it should be the original disc as these are setup as bootable CDs. Depending on your notebook model you could also invoke a one-time boot menu by pressing F7, F11 or sometimes ESC or F1. Some notebooks also use F8 for boot menu access.