memtest86+ has over 2 million errors

"First step - unseat and reseat the memory, sometimes it is just loose which can cause problems.

Next,

If you have two memory sockets and one stick of memory - put it in the other socket and test

If you have two memory sockets and two sticks of memory - rotate both of them.

If you have one socket and one stick of memory - You can try a spare.

In Memtest86+, one error or one million errors doesn't really make a difference, if it is bad, its bad.

As for running Linux for some time, you can just get lucky and not ""hit"" the bad part of memory... or a file could be corrupt and you may not know (but this is rare) - there is simply no easy way to find out.

Typically with Memtest86+, I find that 99% of the time, the problem is related directly to bad memory, but 1%, it is possible that there is another fault such as a blown capacitor which leads to random memory errors."

to rule out other hardware faults with certainty, you will have to run Memtest86+ on this computer again with different memory modules that you have been testing error free on another computer.