My Dell Inspiron N5040 was not powering on. I thought it was because of dirt inside. Therefore, I opened up the laptop, cleaned the fan, replaced the thermal paste (after cleaning off the old paste), cleaned the motherboard with IP alcohol and then put together the laptop again. When I inserted the power adaptor and switched on the AC power, I heard a beeping sound. It was a two-beep sound. I knew that meant no RAM. Therefore, I inserted both the RAM ( 4GB each). The laptop powered on. After some time, I shut down the laptop from the desktop. Later, when I tried to power it on again, it just wouldn't power on. This time no beep sound either. I tried reseating the two RAM sticks. I tried using just one RAM stick. None of this worked. What could be the problem? Does the RAM need to be replaced? Should I buy two new memory sticks of 4 GB each?