3 long beeps of my elitegroup ecs green 320

I was working with my laptop when the screen just got dark, I thought it was the autoshutdown of the screen, but it did not respond even when moving the touchpad or pressing the keyboard I force shutdown it by pressing the power button and press the power button again, it booted, but then froze again and did the black screen again, I noticed the harddrive was not lighting I tried removing and putting back the hard drive and it did not work and started to give 3 long beeps, I tried removing the battery and RAM card from their slots then put them back and put on my unit, still the three long beeps what could have happened? I'm not a computer engineer, could I remedy the problem myself through your step by step guide? the specs of my computer: Elitegroup ECS G320 Laptop VIA C3 NEHEMIAH 1.2GHZ / 256 MD DDR (SODIUM) VIA CLE 226 / COMBO DVD/CD RW, 14.11" XGA TFT (1028 X 768) 32 MB SMA, SHARED UP TO 64 MB / AC 97' CPU VIA C3 Nehemiah up to 1.2GHZ CPU, 64KB L2 cache on die, CPU front-side bus up to 133MHz 376 pin EBGA Core Logic North bridge VIA VT8623, South bridge VT8235 4X AGP bus interface Supports host bus at 66 MHz AGP v2.0 compliant 3.3V PCI version 2.2 compliance ACPI v1.0 USB 2.0 compatible PS/2 keyboard/mouse support System BIOS: AMI BIOS please help, many thanks in advance!