Scan your computer for any Virus using the anti virus installed in your laptop.If your virus free, there are a couple things you can do get your computer working faster. If you using your computer for normal stuff and not gaming. You don't always need more RAM you just need to perform a few maintenance task.
How much of your total memory used when running the apps you usually have running. If this amount is too close to the maximum capacity you have to focus on limiting what is going on on your computer in a passive state.
How much of the total hard drive is being used. You should at least have a gigabyte or 2 free.