My Hardisk keeps taking up space randomly?

Try running disk cleanup. There is an option in disk cleanup to delete all but the last restore point too. Also, you can customize the amount of disk space the trash can uses, restore point usage, and you can even change the amount of space your web browser cache uses.

You can try windirstat to show a graphical representation of your files and folders to see what is eating up the most space.

http://windirstat.info/