Programs running in the Background
Sometimes you will run into the problem where two programs that are installed on your PC conflict with each other and refuse to run at the same time. Or you have a memory leak (a program that uses memory when in use but does not return it after it is done) but are not sure which program is causing it. It can be tricky to find the culprit, because you think that no other programs were running, so what could possibly be the problem? You'd be surprised at how many programs are running on your PC right now. Take a look right now and be amazed. Push Ctrl-Alt-Del on your keyboard right now. You should now see a dialog box labeled Close Programs. In there is a list of some pretty funny looking names. Each one of those is a program running right now in the background. Didn't expect to see that many, did you? Two of the items listed here are always there, that is Explorer and Systray. Those are Windows components and they are supposed to be there. But everything else is a program running right now that could be a possible culprit for your problem. They get loaded automatically every time you start Windows.
How do they get loaded?
There are several places where you can find out. Let's first look at your startup files. Go to Start/Run, and type Sysedit. In the resulting window you'll see many cascading Windows. In the Autoexec.bat window you might find a few lines to start a program. Or in the Win.ini file, look at the load= and run= lines. Anything in those lines after the = sign is a program to be loaded.
Windows also has a startup folder where it checks every time Windows starts. If there are any programs listed, it will start them automatically. You can find the contents of the startup folder by going to Start/Programs/Startup. Didn't realize you had those items in there, did you?
Then there is another not so obvious place: the Windows Registry. The registry key HKEY_LOCAL_MACHINE \ Software \ Microsoft \ Windows \ CurrentVersion \ Run holds a list of programs to be loaded on Windows startup as well.
You probably think how did they get in there since you didn't put them there. Some of them need to be running in the background to function properly, such as a virus scanner. They put themselves into a startup menu automatically when you install them. Others might not need to be there, but they load anyway to be available when you need them.
Now that you know how to find out what programs you have running in the background and how they got there, let's talk about how to do some troubleshooting to find the culprit.
Be systematic
To find out which application is the problem, you need to take a systematic approach. There are two ways to do this: You can shut down all other programs, make sure the problem does not happen anymore, then turn them back on one by one, until it happens again. Most likely the last program you turned on before the problem reappeared is the culprit.
The other option is to shut down one program at a time, until the problem disappears. Most likely, the one program you just shut down is the culprit.
Prevent them from loading
The best approach is to make sure a possible suspect doesn't even load on startup. Windows 98 comes with a built-in utility that lets you control what loads when Windows starts. Start this utility by going to Start/Run, typing msconfig and clicking OK. You'll see a dialog with several tabs across the top. The last tab is labeled Startup. In here is a complete list of items that Windows loads automatically. Note the checkbox next to each item. Uncheck the first item, reboot, see if the problem persists. If so, go back to msconfig, re-check that item, uncheck the next item and reboot. Repeat this procedure until you found the culprit.
For more information straight from the horses mouth on how to use the MSConfig utility, check out this article from the MS Knowledge Base.
Shut them down
There is also a way to shut down a program that runs in the background of your current Windows session which does not require a reboot. You can push Ctrl-Alt-Del to bring up the Close Program window. Now highlight the program you want to disable for now and click End Task. The Close Program window should disappear. Sometimes it can take a few seconds for the program to unload, so be patient. Other times, you might get another window informing you that the program is not responding. That window will have its own End Task button that you should push to close it for good. Repeat this process for every program that you want to shut down.
Be careful: Do not push Ctrl-Alt-Del while the Close Program window is still on the screen, it will reboot your PC, reload Windows and all those programs you were just trying to shut down, and you'll have to start all over again.
Also, remember not to shut down Explorer. That's Windows running and it's supposed to be there.
The main advantage of the first procedure is that it will completely prevent that item from loading, and will not load that item again until you re-check its box. The disadvantages of the second procedure are that it will load all programs again as soon as you reboot and that it's not as thorough because it might not completely get rid of the program or unload all parts of it.
Either way, you should be able to isolate the program that's causing your problem. With that knowledge, you can take the necessary steps to correct it, e.g. uninstalling the program if it is no longer needed, upgrade it if there is an update, upgrade or patch available from the manufacturer, or at least temporarily disable it to avoid the problem when applicable.