I have a acer travelmate 240. when i connect power cord there appear a tap sound.
tap...tap...tap.. from speaker power switch not working mean laptop not booting, no bios screen appear on monitor. and "A" lock LED blinking continuously.
This sounds like a power issue. Have you tried with another power cable? The noise you hear may be related with a power port issue. Remove battery and disconnect the power cable. Hold the power button for a few seconds and reconnect the power cable. Try to boot again. If the issue persists and you have a warranty, I advise you to contact the manufacturer's support and get more suggestions.