How can you login to your work PC from your home PC?

Sorry, it simply can't be done, you would need some kind of large network that connect all the computers in the world through sockets. The only thing you could do would be to run a long Ethernet cable from your house to your work.

The above answer is neive and incorrect. Remote access is built into Windows Server products and many many companies allow you to remote desktop into your work computer from your home computer. Search for "routing and remote access Windows server" from any search engine to receive documentation on how to configure this Windows Server role to suite this purpose. RAS, VPN, PPP Tunneling, are all terms and technologies that provide this functionality.

The above poster is either extremely inexperienced or just kidding around. I hope he's just kidding because that advice is horrible.