On Dell laptops, this represents a problem with the RAM. Take the RAM out and use canned air to blow the RAM clean and to blow out the channels into which it fits on the motherboard. Then, take only one stick of the RAM and seat it in the lower of the two slots. Be certain that the memory is fully inserted - most of the line of contacts should be fully inside of the slot. Power the computer on. If it doesn't beep and boots you know that stick of RAM is good, probably. If it doesn't, then you know that stick of RAM has gone bad. Power the machine back off and try again with the second piece of memory. If both sticks show as being good, then go ahead and insert both and power on. If you again get the beeps, power off, switch the RAM in the two slots, and power back on. Assuming everything boots up properly at this point, in Windows, Click Start and type Memory in the box. Select the Diagnose your memory option. Choose, "Restatrt Now and test my memory for problems" and your computer will run a fairly comprehensive test of the memory and let you know if it finds any problems.