[SOLVED] How can I get my system to use both of my ram slots?

[Tiny the trash cat]

System
OEM/Model: HP Pro 3400 MT
Motherboard: Foxconn 2abf CPU: Intel i7-2600K GPU: PNY Geforce GTX560 ti RAM: 2x 2gb Crucial



For some reason my system only is using one of the RAM slots at a time, I've tested each slot by itself with ram.

I start the computer and the BIOS tells me there's only 2gb in there even with both sticks in, I ran CPU-Z and resource manager.

Cpu-z told me there 4gb of ram and RM told there's only 2gb
How can I get my system to use both of my ram slots?

 

[Calvin7]

2 x 240-pin DDR3 DIMM slots Supports Dual Channel DDR3 1333/1066 MHz non-ECC, un-buffered memory

Crucial is a major memory manufacturer that makes a lot of different memory. What you have may have been bought at different times, be a module sold as a Single Module and added to existing memory, be Registered memory, or be a pair of modules in a kit, or memory with an unsupported speed. Memory is usually identified by a part number.

Some people think that as long as they put something in the slot it should work. That often is not the case.