I have installed wine and i am afraid that viruses will affect my PC now. I will not open any other .exe file other than mine one (which i use everyday)
Yes.
No. You could enable that sort of autorun scripting if you really tried, but it's not something Ubuntu ships with.
What happens if you run anything through wine? A virus is just an application that does particular things. If wine supports those things, they're going to work as designed. If wine doesn't, you're going to see a bunch of messy errors.
It's really not possible to give one answer that covers all viruses.
I generally consider it better to just avoid them in the first place.
Having seen another answer claiming that Wine can't hurt anything, I think it's important to add that it's not true. Wine has access to more than enough to ruin your day.
For your convenience, your home directory is symlinked to My Documents. That means you can save things easily from Wine applications but it also means that even a basic virus could, for example, encrypt all your Ubuntu documents and hold them hostage.
