If your installed RAM modules are faulty or not connected properly, it can cause a range of problems, from system crashes to unexplained error messages. Windows includes a memory testing tool of its own and there are several reliable third-party freeware alternatives available, too. If problems are detected, try reseating the RAM modules in their slots before replacing them.
Windows Memory Diagnostic Tool
Move the mouse to the top right corner of the screen (or swipe in from the right on a touchscreen) and launch the Search charm. Search for and run the "mdsched.exe" utility. Your PC must be rebooted to run a memory check -- you can choose to do this immediately or schedule the scan for the next time you restart the computer. The utility displays details of any errors that it discovers on screen or gives your memory a clean bill of health. Check that the reported amount of memory matches the amount of memory you expect to see installed -- this can also be checked from the "System" link under "System and Security" in Control Panel.
A variety of free third-party alternatives can be used to test the memory in your computer. Memtest86+ is one of the most well-known and is recommended by RAM manufacturers -- once downloaded, you can use it to create a bootable disc or USB drive to test your RAM. Other similar tools include My Memory Monitor, RAMMon and PC Wizard.
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