When I switch on my computer it makes a beeping continuous sound and will not boot up?

One possibility is that the power-on self-test (POST) the computer performs at boot has detected a problem and is generating a beep code describing the issue. The codes are usually listed in the system or motherboard documentation. Memory, video, and power supply errors are common problems.

I replaced the battery CMOS but still hear the beeping sound when power on. I do not get the computer to boot up, so can not see anything on the screen. How do I get it to boot pu?

When I press the re-boot power button below the main power button the beeping sound stops. I still do not have the system coming on.

Until the meaning of the beep is determined by consulting the documentation and the issue addressed, boot will not progress. POST errors that result in no video are often memory or video adapter related. You can blindly try removing and reinstalling the memory modules and video adapter to see if it has any effect. Purchasing and installing a POST diagnostic card can also indicate where POST is stopping, however it too generates codes that must be correlated to issues which are referenced in the documentation.