Time
5 hours 33 minutes
Difficulty
Beginner
CEU/CPE
3

Video Description

Establish Theory of Probable Cause In this lesson we explore the concept of Establishing Theory of Probable Cause. This is basically a strategic process of elimination by ruling out certain causes which automatically create problems. You'll learn to determine which components to hone in on, what automatically assessments to make based upon the issue presented and how to conduct an assessment to accurately narrow down the root causes of the problem(s) being experienced.

Video Transcription

00:04
now our next step after we've identified the issue and we've taught to whoever is using the computer, and we've maybe
00:11
figured out exactly where the issue lies and what the problem is Next. We want to establish a theory of probable cause. Now we establish a theory of probable cause. We're essentially going through the process of elimination. There may be a lot of issues that could cause a particular problem on a computer. Say the monitor is blank or the wire. We can't connect to the wireless,
00:31
and we want to start ruling out
00:32
what may be causing this issue. One of our first main distinctions is the problem. Hardware or software based? Is the problem a physical problem with peace or component of the computer? Or is the problem with a setting or a program or an application that's installed on the computer or part of the operating system?
00:51
Once we can make that distinction,
00:53
we can begin narrowing down even further. What particular hardware piece, what particular? What particular software will particular application we may be having an issue with
01:03
Now,
01:04
hardware, maybe physically obvious hardware problems. May hardware problems do present themselves in ways that aren't physically obvious, such as a bad cable that just doesn't show a screen that could also be like a setting or change on the screen,
01:21
or a bad video card that's presenting lines across the screen.
01:26
But hardware problems may also be things like grinding noises inside the computer that aren't presenting any actual problems when the user's working on the computer, but they hear a grinding noise and the computer. Or they smell a burning smell, which is very bad. Or they see physical smoke, which is very, very bad. So
01:46
hardware problems
01:47
will be those physical. Maybe those physically obvious problems that we can hear, smell or see now
01:55
typically physically obvious problems are are going to be hardware related. You're not gonna have a you're not gonna install a program that is going to make your your fans start your fans start grinding or your hard drive start grinding. But it is possible, especially if there's a lot say. If there's a program that's using
02:15
ah, lot of hard drive usage and it's rapidly spinning the hard drive or starting to overheat your computer,
02:20
then those physically
02:22
physical symptoms the fast spinning fan, the grinding hard drive, maybe software related. So just because a problem is physically obvious doesn't mean it's a hardware issue. And just because the problem isn't physical, it may be on the computer as we're working on. It
02:38
doesn't mean it's just a program on the computer. It can be interchangeable, so we want to remember that.
02:44
But we do want to try to narrow down if the problem is hard related or software related as soon as possible.
02:51
Now,
02:52
once we determined hardware software, we may want to narrow down which exactly the part or the program that is causing the issue is its network related. We may want to start start narrowing down some of our network settings,
03:05
start eliminating some variable C for acquiring an I P address, see if we can ping our default gateway. See if we can. Paying past our default gateway.
03:13
I didn't start Satan going through those issues and going through our checklists,
03:19
and we can eliminate variables in other ways. If we think we may have a driver issue or we think that there may be a program that's causing an issue on our computer, we may wanna boot into safe mode or we wantto may want a boot into safe mode with networking. And then once we're in safe mode, start slowly and systematically. Starting service is
03:38
starting programs and see, as we're starting the service's and programs
03:42
if the issue starts up again so we can start eliminating eliminating variables and say, Okay, well, I can boot and safe mode. So it's not this this or this issue or I can't boot in safe mode. So now I have a new issue entirely.
03:58
We may also do things such a swap Ram modules. If our computer we're trying, we're trying to turn on the computer and we're just getting beeps.
04:05
We may want to check our round. We will receive the RAM. Start swapping the ram in different slots to see if it's the slots or bad or the ram is bad. Maybe take out one RAM module at a time and we'll be able to narrow down if it's the ram or if it's Scott's, or if it is the RAM which RAM module has the issue? So it's just these different
04:25
different tasks that weaken d'oh!
04:27
Different logic, logical operations that we can perform to say. Okay, we're essentially creating a flow chart of sorts in our mind, we may even want to for working on a help desk or on the desktop support create a flow chart as we're working overtime in order to help ourselves and help others. We say, OK,
04:46
I have this issue.
04:47
I say we have, ah, single symptom that could be one of dozens of different causes. We don't want to start tackling those problems. Those possible causes wanted a time we don't want to say Okay, well,
04:59
it might be the ram or might be a program or might be an application. So I'm going to check this program and this RAM module and this other program in this service.
05:08
We want to try to eliminate as many variables at once as possible so we can do things like boot and safe mode. And then we boot and safe mode successfully and we say Okay, so it wasn't a hardware issue. It's a software issue or it's not one of the our core operating system files. It's an additional file
05:27
and then we say OK, so I was able to boot into safe mode. Is it? Maybe it's a network issue, Kanai boot into safe mode with networking.
05:33
Yes, safe mood with networking works and I can connect to the Internet in safe mode with networking. So now I've eliminated some of my core Internet settings. I've eliminated some my core operating system files, and I'm left with some drivers. Some programs, some service is. So
05:50
we want to eliminate as many a cz many possible variables at once through different logical tasks that we can perform different,
06:00
different steps that we can perform that will allow us to delineate where our problem is and narrow down where exactly our problem is.
06:11
So
06:12
then, lastly, after we've gone through a process of elimination, or maybe we get stuck at a certain point and we can't really figure out where to go next, we may be able to research the issue, researching our issue maybe ever anything from going online and checking different forums to checking TechNet or even going and referencing
06:30
previous previous help take tickets.
06:33
If we work in an environment where we're say on a call center on a help desk and there's a ticketing system that we can search through where there's a knowledge database that we can refer to this knowledge database or this ticketing software may provide us with a great source of researching these same issues. We type in some key words we type in. Some of
06:53
the are the features of our problem.
06:55
And then, look, this person had the exact same issue. Let me see how they solved it or see if they had to escalate the issue. So researching our issue may give us a couple of shortcuts to determining where our problem is or may help us along if we get stuck.

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Instructed By

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Anthony Harris
Systems Analyst and Administrator at SAIC
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