Are we talking about a desktop or a laptop?
Without knowing I can't guide you to good.
It sounds like you now have 2 sticks of ram. They can only be "disabled" by physically removing them.
What you can do is remove 1 of the sticks and see what happens. If the remaining stick fails, then swap with the other stick. In other words, process of elimination.
Now for our speech (and how to run memtest).
If you have more than one RAM module installed, try starting computer with one RAM stick at a time.NOTE Keep in mind, the manual check listed above is always superior to the software check, listed below. DO NOT proceed with memtest, if you can go with option AB.
If you have only one RAM stick installed...
1. Download - Pre-Compiled Bootable ISO (.zip)
2. Unzip downloaded memtest86+-2.11.iso.zip
3. Inside, you'll find memtest86+-2.11.iso
4. Download, and install ImgBurn
5. Insert blank CD into your CD drive.
6. Open ImgBurn
, and click on Write image file to disc
7. Click on Browse for a file...
8. Locate memtest86+-2.11.iso
file, and click Open
9. Click on ImgBurn green arrow to start burning bootable memtest86 CD:
10. Once the CD is created, boot from it, and memtest will automatically start to run.
The running program will look something like this depending on the size and number of ram modules installed:
It's recommended to run 5-6 passes
. Each pass contains very same 8 tests
This will show the progress of the test. It can take a while. Be patient, or leave it running overnight.
The following image is the test results area:
The most important item here is the “errors” line. If you see ANY errors, even one, most likely, you have bad RAM.