it could be there is lots of programs starting with windows,slowing it down.
type "msconfig" and click ok
click the start up tab on the right and untick everything apart from your AV and firewall.
click here to find out what the programs are.
click apply and restart the computer,ignore the warning that pops up.tick "dont show again"
your programs will still start when you need them,just not load automatically with windows anymore.
try also running a disk cleanup and defrag.