Whenever i start my dell precision tower 5810 i get a black screen with this message "ERROR! Memory configured incorrectly. Please enter Setup for Memory Info details." i assumed something was wrong with my hard drive so i bought a new one today and to my surprise same message could someone please help me out please?
Not a Hard Drive problem, as you found out. It's a RAM problem.
When was last time you changed the motherboard battery? This might be a good time to do that too. CR2032, 3-volt coin cell battery. If nothing else than to rule battery out as part of the problem. And removing the battery may clear the error message too.
Power off and unplug
Press/hold power button for ~15 sec
Open case and remove motherboard battery
Press/hold power button for ~30 sec
Reseat RAM modules in slots and use canned air to clean out the dust
Close case and see if it boots now
Read the 5810 service manual on Dell's support site for instructions to remove/install RAM modules and battery.