If you have a desktop PC it is very (fairly) easy to replace the current hard drive with a large one (say 2Tb).
You make an image of your current hard drive with say Macrium Reflect Free Edition, then take out the current hard drive, put in the new empty one, and do a restore from the image you took.
The other option if you have a desktop PC is to put an extra hard drive in the case. Most desktop PCs have a space for a second hard disk, so buy a 2Tb drive, put it in your case (leaving the old one in) and then work with two hard drives.
Increasing RAM is easy to do. Find out the maximum ram your motherboard takes, and how many slots it has, and buy the maximum memory.
So if it can take 16Gb and has two slots buy two 8Gb memory strips.
Note: Make sure your version of Windows can support that much memory.