How much RAM do you have, and what are you running on it? You have a really general issue here. Do a full defrag, run spyware scan with Malwarebytes, and do a full virus scan.
If after all this it's slow you may just need to re-intsall Windows. From the age of the computer (has a Mobile CPU) you probably have it jammed with trial software, old games, 2-3 anti-virus softwares, 4 anti-spyware softwares, etc..
For the re-install of Windows, I don't recommend re-using your old hard-drive unless you know all of your data is backed up. Buy a new drive and find a buddy who can install it and get an external case for your old drive to copy your files back,