When I look in Windows Task Manager, it is showing 55 processes running at startup. I don't know which ones are okay to remove, or if I should, but that seems like a lot.
Go to Start>Run>msconfig>Ok. Take a look at the "Startup" tab, these are all the processes set to start with Windows. Look each one up via a search engine and disable what you feel okay with.
Yes, I agree 55 processes is quite a lot for a desktop PC. I have usually around 30-35 after booting (although I'm using Vista, it has some different services).
You probably have things like jusched.exe, quite unnecessary Java update checker, reader_sl.exe, Adobe Acrobat Reader "speed launcher", another useless thing, etc.
The only processes that need to be checked to start at boot are:
Anti-virus program
Firewall is you have one.
Touchpad if using a laptop
Network process is a network us set up.
Nothing else!. I run a steady 36 on my laptop. Another source of some of those processes are the Services. Any not needed or being used should be either Disabled or set to Manual. here is a good site for help with services. Care mus be taken to check The Dependency tab.: