While modern versions of Windows have largely overcome the performance rot problem that was once the bane of users, it's still possible for applications to silently add auto-run utilities that slow down your PC's boot time and overall performance. Here's how you can manage which applications and services run when Windows 10 starts up and, more important, figure out which are necessary or useful.
The key is Task Manager, which was nicely overhauled in. You will occasionally be prompted by Action Center—the Windows utility which puts a flag icon in your system tray—to examine your startup programs. But you can run Task Manager at any time by using Start Search (search for task manager) or by right-clicking the Start button or taskbar and choosing Task Manager from the pop-up menu that appears. When Task Manager starts, click "More Details" if needed and then navigate to the Startup tab.
Over time, Task Manager's Startup interface will provide information about which startup programs impact boot time the most. But that's not necessarily helpful. For example, Google Chrome may actually impact boot time a lot, but if you use it daily, you still won't want to disable this program. And you're probably not really booting your PC all that often anyway. (More important, I think, is the impact these programs can have on overall system performance. And that's not measured here anyway.)
The other issue is determining which programs should or should not startup when your PC boots.
For example, what the heck is "Btmshellex" in the list on my own laptop? I don't recognize that name, and there's Publisher listed, which is suspicious. Fortunately, Task Manager lets you find out what each program is: Just right-click it in the list and choose "Search online" from the pop-up menu.
When you do, your default web browser will launch and display search results for the program you selected. In general, I find the results from Should I Block It? to be particularly helpful.
In this case, it turns out that Btmshellex—really Btmshellex.dll—is a process used by my laptop's Intel PROSet\Wireless Bluetooth chipset, and it's related to the Bluetooth Shell Extension, that little blue Bluetooth icon that appears in the system tray. So it's safe, which is good. But it's still not super-clear if I need that running. Do I even use Bluetooth on this PC? In my case, the answer is no, so I can safely disable it: Right-click it in Task Manager and choose Disable.
Equally problematic are the entries "Adobe Reader and Acrobat Manger" and "Adobe Updater Startup Utility." On the one hand, it's advisable to let Adobe automatically update its applications on your PC, since these applications are such a common attack vector for hackers. But on the other hand, you may not appreciate—as I do not—Adobe putting an auto-run application in your startup sequence so that its applications run a bit faster later on. So if you're going to consider disabling one of these, you better understand what they are.
A little web research using the aforementioned "Search online" option reveals that Adobe Reader and Acrobat Manger—or AdobeARM for you Adobe fans—is necessary. This is the utility that automatically keeps Adobe Reader (in my case) up to date. So that one stays.
"Adobe Updater Startup Utility," meanwhile, performs exactly the same function, but it does so for other Adobe applications, such as Photoshop Elements, which I also use. Frankly, this one is less essential, but I'm going to keep it running so that Elements is updated as needed too.
The Task Manager shown above is from a very clean version of Windows—heck, I just install the Windows Technical Preview on that particular PC, so that's not surprising—but this interface will get crowded with entries as you keep using Windows and install more and more applications. Be sure to check in from time to time, and of course Action Center will occasionally pipe up to remind you as well.