|The long beep will be related to either the RAM or graphics card. If you have a graphics card, remove it and try to boot again. If issue still persists - remove RAM completely and listen for a different beep sound. If the beep sequence changes, then straight away you know its the RAM!|
If you have 2 or more sticks of RAM, try one at a time. (It is possible that both sticks could be faulty if a surge or something has occurred..)
Lastly, check your BIOS to make sure your CPU fan alarm isn't set too low! By default they are usually set to sound an alarm at 1600 RPM so increasing the RPM slightly will prevent the beeping if this is the issue.
Hope this helps.