Advance Auto Parts will read your codes for free on most cars 1996 & newer.
You can get a free diagnostics test at some major-chain auto parts stores.
Memory Diagnostics
Many modern computers have a BIOS firmware that includes a memory diagnostic. Software is also available on the internet that can perform memory diagnostics. Many are free. A good source of memory diagnostics is the Hiren BootCD available for free download. It is a bootable CD that can perform memory testing and a lot more.
$199 at Quest Diagnostics without insurance
paragon alignment
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DXDiag meaning " Direct X Diagnostics" is a diagnostics tool used for to test Direct X functionality and to troubleshoot video or sound related hardware problems
There are lots of local computer companys which will probably give free diagnostics.
Key on, off, on, off, on.
SIW is a free program that offers diagnostics for windows. There are also Live things you can download to a CD and use it when you boot up like Hiren's Boot CD.
POST(power on self test)
The codes have to be removed with a scanner. Go to Auto Zone and they will do it for free.