Anything is possible. And I think that if someone wants to target someone they will get in no matter what. On my computer I am sure that they would be so bored they would leave without even a whisper.......lol
If someone is at your house and wants to log onto your Yahoo account,
There are some things you can do that can help.
You can turn off Auto Complete, and don't click Remember me when you sign in.
Or are you talking about from another computer?
Here is an article that tells you how to Hack proof your computer. http://www.pcworld.com/article/id,17759-page,1/article.html
First thing to do is to get a firewall........either a hardware one or a software one like Zone Alarm it is free.
Get the current version of your anti virus software and keep it up to date.....the best way is to let it download the updates for you.
Get the Windows updates.
Every week or so run a program like Adaware or Spybot Search and destroy. You can Google search for them.
If at all possible don't let anyone else on your computer.
Now those things will help but in the end if it is really scaring you.
Don't use messengers or email , unplug the internet from the computer and shut it down.....
That is what someone told me he was a geek and no fun at all..........lol
There is only so much you can do but try and keep aware....
I always check my task manager to see what is running. If there is something strange going on in there then I check it out. Task