We call this 'throwing hardware'. Try a few things first.
Start(the little round thing in the corner), control panel, system, advanced system settings on the left side.
Once in there, you'll see four or five tabs. If the 'advanced' tab is there, you are logged in as an admin and can make changes. Locate the 'performance' box and click settings. Remember this location because you'll be coming back here several times.
First, you can adjust how Windows reacts to you, and set the optimization of the visual effects. Your best bet here is to choose 'custom' and start messing with all those little radio buttons down below. Some of them will really slow things down on startup and when running various apps. Some have little effect. Mess around in here first, and see if you can make some improvements.
After you fool with that for a few days, come back to this location and click 'performance options' and 'advanced'. Now, you are really going to mess things up! See if the resource allocation is set for programs or background. Obviously set it for programs radio button. Then, to really have fun, start messing with the demand page size. Click 'change' and a little box will come up allowing you to remove the safety of Windows page management and go rogue. All the advice I can give you here, is make notes of where you've been.
Sometimes a bigger page will work better, and sometimes a smaller page will work better. Here's the thing, you are messing with the internals of how Windows gets to play with your computer. Windows has a habit, since back in Win 98 time of sucking up all avail RAM and loading all kinds of junk that you rarely/never use. They do it, because they can! If you make the swap file too big, Windows may load more junk on start up. If you make it too small, Windows may not load enough junk, and need to go swap for a while. It's a crap shoot, and I will make NO recommendation on what to set, because each install is unique.
Before you throw hardware, try fooling around with the settings in the Advanced tab of System properties and see what happens. If you still want to throw hardware, a SSD is a nice improvement, but there are grades of SSDs out there, and you may not see much gain unless you are swapping/paging constantly. You've already made the big cure and added more RAM, which Windows saw and instantly filled up with OS junk.