Answer: A. Upgrade to a 64-bit version of Windows.
Explanation: In this situation, you are most likely using a 32-bit version of Windows, which can only address a maximum of 4 GS of RAM. Some of the 4 GB is used by drivers hence it only reports 35 GB of System RAM. Upgrading to a 64-bit version of Windows should fix the problem.
The BIOS should display the total amount of system memory during POST. If it does not count the proper amount of memory, verify that the memory is inserted correctly. In most cases, you will not need to change the memory timings. When you do it is typically because the system is unstable or crashes. Testing memory helps you identify when specific memory storage locations are going bad. Device Manager will not enable memory not recognized by the BIOS.
Explanation: