You "can" check these processes to see what they are, whether they are essential, or recommended, or non essential, or just plain virus/spyware. But it is a process of elimination, meaning you will have to check each one individually, then decide what you want to do.
First step, go here; http://www.answersthatwork.com/Tasklist_pages/tasklist.htm , and check each process in Task Manager > Processes for more information.
If you have any viruses you can then investigate further.
If you have running processes that you don't need, eg RealPlay.exe may be one. You can check the program itself to turn off it's "load on start-up", and turn off it's SystemTray icon, etc. There may be other programs you have installed that run in the background without your knowledge.
Many of these may be Services that Windows XP sets, or that installed programs set, eg an anti-virus or firewall program.
You can check the Services for your computer by going to Start > Run, typing in "services.msc"< (without the quotes), and clicking OK.
In the Services dialogue window, choose the Extended tab down the bottom, and highlight each service for a description of what it does.
Here you can disable, set to manual, or leave as automatic as you wish. Be careful, many are required by Windows, so you will have to research them more. But some can be safely disabled. EG on mine the first is Alerter, used for Administrative alerts. as I am the sole Administrator and user of my PC, I have disabled this.
I hope this helps.
When I hit CTRL+ALT+DELETE and get the task manager window, theres always a _ton_ of stuff under processes, that I don't want running there. It's wasting my memory and sometimes gets annoying. I've got throug the whole MSCONFIG>startup routine and I've run many different sorts of spyware destroyers, but they still persist. It seems that most of the processes aren't even spyware, iTunes (i always see iPodService.exe, or iTunesHelper.exe running), and RealPlayer (realsched.exe and realplay.exe is always there) for instance seems to be _eternally_ running on my system even though I use them quite rarely. I want them to go away forever! Any help is greatly appreciated.