yes windows does take a LOT of processes to keep running and it seems the next version that comes out has more. as I speak I am on my windows XP system with two IE windows and yahoo messenger running only and I have 55 open. what you have to think about is what is running in the background. Me? AVG antivirus, Spybot Search & Destroy antimalware software, cisco vpn software, wireless networking programs, intel graphics software, etc.
but never underestimate the hackers too. you need to have a good antivirus software running as well as have a good anti-malware software running. you can never be too sure. It is good that you are checking your running processes. This is a good start. You can usually find out what most are for. Like the ones that start with HP are USUALLY for hp printers, but if you don’t have any installed that is an issue. You can narrow it down by name. Then start to Google items by name like “jushced.exe process” which will come back stating that it is the Java Updater scheduler. I have not found a process that I could not find using google so far. But if you do, then that is what this site is for! Hope that helps.
In addition to applications and programs running in the background (or on the system tray) some processes are also windows services that are running. For example, if you look at your processes you will likely see spoolsv.ex in the list. This is the spooler service, when you stop the service this process will go away.
A common practice in hardening a system is to disable un-needed services.