Accessing my computer @ work from home

I have a stand alone PC that I do all my work on when at my business. What I would like to do is be able to access the files on my work computer from my house on the days that I am sick or have a day off. I have a 56k v90 modem on my work system. I need step by step on how to make the connection between the two systems. If the answer to this will not fit in the spaces allowed, please email the information to me at joep@royalnv.com