Download a freeware ap named Startup Inspector which will enable you to view and identify the programs that start automatically when Windows starts.
Most of the ones you will see there do not need to be started when you turn on the computer.
What you do need to startup are your anti-virus program, any anti-malware aps you will find listed there and your firewall.
You can safely disable programs such as Word, MS Office, Realplayer, Adobe, Quicktime etc, which will then start when needed and not run in the background taking up resources.
Startup Inspector (manages startup menu – helps you identify aps in the startup menu so you can disable unnecessary programs from running in the background when they are not needed)
Startup Monitor (a small freeware ap available on the same page to notify you and require your permission for any program to add itself to your startup menu)http://www.windowsstartup.com/download.php