Go to start-run and type
msconfig
in the box. Click Enter.
Now click the Startup tab and see what programs are starting automatically at log in. Some of it essential such as your firewall and antivirus software but you may have lots of progs starting that you won't use that session.
If you know for sure what something is, such as Office, you can untick tick it and reboot. Be certain you know what it.
Lots of progs put themselves in the startup and it is not necessary. You don't need your printer software, mp3, camera, satnav, games, instant message prog, and so on to be running automatically all the time.
It should start up a lot faster without loading all those progs.