PC not detecting RAM.

So, i have 2x 2GB and 2x 1GB RAMS installed. The problem is that my pc, only detects 4 out of 6 gb RAM. I had the same issue 2 months ago, but after some days, the RAM was finally detected. 3 days ago i had to check something and i have the same problem. Any ideas? (They are compatible with the motherboard). Thanks!
Report as:
Offensive Spam Harassment Incorrect Board