Most computer users live in fear of a crashed computer and lost data, or are frustrated by a computer that seems to take hours to perform the simplest task. The trick is to learn from these problems and either fix the computer before the worst happens, or at least make sure it never happens again.

This is not work that can only be performed by experts. Even a blue screen can be helpful, since Windows uses it to deliver a Bug Check Code, which gives some hint about the cause of the problem.

Thus, the message KMODE_EXCEPTION_NOT_HANDLED indicates a problem with a driver. Microsoft provides a complete list of all check codes — and possible solutions — online. Such tips are necessary; otherwise any effort to fix a computer can quickly turn into a waste of time.

“Unfortunately, the diagnosis is anything but easy,” says Hans Ludwig Stahl, director of the Institute for Computer Science at the Cologne University of Applied Sciences. Problems can stem from issues with either hardware or software. Or the PC could be having resource issues related to working memory or hard drive space.

Stahl recommends seeking the source of the problem in the recent past. “Maybe the problem cropped up right after putting in a new piece of hardware or installation of some new software.” If that’s the case, remove the potential source of the problem as a test. Maybe the computer will work fine without it.

Sometimes combinations of hardware, software and operating system simply don’t work, says Stahl. “That can always happen with open systems like Windows.” In a worst case scenario, that can mean living without the problem hardware or software. Sometimes a patch or a new driver from the website of a manufacturer can help. Or maybe the computer just wasn’t prepared properly for the new hardware. For example, new working memory will only function with the right settings for BIOS, the foundation of the PC’s firmware.

In such a case, beginners should leave any major changes to experts.

“A sudden crash usually indicates defective hardware,” says Harald Goerl, who focuses on operating systems and computer architecture at the University of the Bundeswehr in Munich.

On the other hand, if problems develop slowly over time instead of all at once, it indicates a resource problem, such as a lack of hard drive space or too little working memory. This can be solved with more kit, or by cleaning out the hard drive.

If a computer crashes after it has been running for a while, other problems might be manifesting themselves.

“That can just be a problem with heat,” says Stahl. Many computers indicate overheating with a beeping sound — not from the loudspeaker, but directly out of the computer’s housing. In such cases, the PC should be opened so the ventilator can be cleared of dust. Laymen can easily do this task, usually with a small brush or pressurised air.

If, after a hardware check, a cleaning of the housing and a virus scan, the problem still exists, then users will have to consider the possibility of a problem with the operating system.

“That is often the biggest problem and it can never be completely ruled out,” says Goerl. Just the core of Windows has 70 million lines of programming code, creating more than enough possibilities for problems to crop up.

If that’s the case, consider a new installation — but only after you’ve exhausted all other options. Also consider whether Windows’ regular updates are making the system slower.

“The operating system is always getting bigger because of them,” says Stahl. The bigger the system, the longer it takes to boot up or call up programs. But don’t avoid the updates either, he warns, as they usually contain files to close up serious security gaps.