How to use MacBook from my PC
You can install a free, open-source VNC client and server on your PC. You can then use the PC to connect to the Mac through Apple's built-in screen sharing capabilities, which can use the VNC protocol, or you can find a free VNC client for Mac OS X.

VNC stands for "virtual network computing"; it is a well-established protocol for letting one computer view the screen on remote computers and use the keyboard and mouse to control them, all over a network connection.

For your PC, check out RealVNC.

I haven't used this to connect between a PC and Mac in several years, but you can configure things on your Mac to permit VNC on your PC to connect to your Mac. You may have to make adjustments on your Mac to your firewall and open ports. Other people here can probably provide more details on configuration.