There are two pretty easy ways to do it for free without much work.
1. Use Windows Remote Assistance.
-(From your employee's computer) Click the windows logo in the bottom left of your screen OR press the windows button + R to bring up the RUN window.
-From here type "msra" and click "Invite someone you trust to help you". There are multiple options, easyconnect, invitation file and outlook email direct.
-Go ahead and click invitation file because it will work with any version of windows 7 or vista.
-Save the inviation file and write down the password that comes up in the window (or copy paste).
-Email the employee or yourself the invitation file and password to connect.
-Open invitation file on employee's computer and type in password.
-The employee will accept the request for assistance by clicking OK. Now you will be able to view the employees screen. To control the employees screen click the remote control button on the top panel of the Windows Remote Assistance window. The employee will have to click OK for you to take control.
2. Download and use TeamViewer or similar program - http://www.teamviewer.com/
Teamviewer is even more simple. Download free version on both computers, write down the User ID on the computer you wish to monitor. This is found on the left side of the TeamViewer application. Now open TeamViewer on your computer and enter the User ID from your employee's TeamViewer and connect.
Teamviewer is nice because you will be able to save the connections and access them again quickly later if you need to.
Let me know if you run into issues.