Once upon a time I bought a new laptop and all's well. Several months later, however, it developed a problem: Within 10 minutes of connecting to the internet us

Once upon a time I bought a new laptop and all's well. Several months later, however, it developed a problem: Within 10 minutes of connecting to the internet using the onboard modem (this was really a while ago) the OS will crash after ~10 minutes of normal operation. Various software patches and driver updates were promptly applied but to no avail, once connected no matter what actions you take it will consistently throw a BSoD without any hint of trouble after a few minutes. Considering the fact that the system was 100% stable offline it seemed fair to conclude that the modem was faulty. Except that when I procured an external modem it reproduced the exact same issue. A lot of time was wasted trying to figure out what happened. Several fruitless rounds of OS reinstalls later I started to swap test any removable component out of desperation (there really wasn't many on a laptop) and voila the problem went away once a particular stick of RAM had been removed. Later tests found that it will pass most tests in MemTest86+ except this a copy operation over repeated runs. I have no idea why the symptoms were so peculiar, perhaps when using dial-up connections the OS had been repeatedly loading the network stack in the memory address close to the affected blocks and after a while it will inevitably encounter a IO error and crash. This is just one personal anecdote, but with a complex system it is certainly possible for RAM issues to appear like other kinds of failure.