Yes, you can; if the other machine is still running.
If the other computer is dead, NO..
It is called Remote Assistance.
http://windowshelp.microsoft.com/Windows/en-US/help/398b5eda-aa7f-4078-94c5-1519b697bfa01033.mspx#EN
| What is Windows Remote Assistance? | |
|---|---|
| When you're having a computer problem, sometimes you might want help from someone else. You can use Windows Remote Assistance to invite someone to connect to your computer and help you, even if that person isn't nearby. (Make sure you only ask someone whom<br> you trust, because the other person will have access to your files and personal information.) After connecting, the other person can view your computer screen and chat with you about what you both see. With your permission, your helper can use his or her mouse<br> and keyboard to control your computer and show you how to fix a problem. You can also help someone else the same way. |
Mick Murphy - Microsoft Partner