With both Windows XP and Vista, programs run as either processes or services. If they load on startup, they either do so from the Startup folder or from the Run section of the registry, though this may be in conjunction with other programs. It may sound as if this all would make it much more difficult to find out what is running on the computer when it starts up, but it really doesn't make it harder at all.
There are several ways to find out what launches and runs when the computer starts up. It should be pointed out that some of the programs should be running, but some don't need to be and can lessen the efficiency of the computer.
The most detailed way to see what is running is to run System Information. To do this, click the Start button, click All Programs, click Accessories, click System Tools, and then click System Information. It usually takes a few seconds for the System Information screen to update, so be patient.
On the left side of the System Information windows, locate 'Software Environment' and click on the plus sign in front of it. You should then see a number of labels under it, including Startup Programs. Click on Startup Programs and wait for the screen to refresh.
You should then have a listing on the right hand side that will tell you what is set to launch automatically on startup.
You can also press the ctrl, alt, and del keys on the keyboard, all at the same time, then select Task Manager. (Alternately, you can right mouse click on a blank place on the task bar and select Task Manager.)
In Task Manager, click the Applications and then the Processes tabs to see what applications and processes are running on the system at any given time, such as immediately after startup.
Yet another way to see most, though not all, of the programs set to launch on startup is to click the Start button, click Run, type "MSConfig" (without the quotation marks) and press enter. When the configuration editor opens, click the Startup tab. The programs that have checks in the boxes are the ones that are loading on startup. (Unchecking them prevents them from loading on startup, however take care with removing the check marks if you aren't certain what an item is.)
For all the computer's complexity, it was designed to give people multiple ways to find out what is running and also what loads when they turn the computer on. The ways listed here are only some of the ways to find out, too. In fact, as Windows has evolved, more and easier ways are being developed into the operating system to allow you more control over your own system.