If I only connected my PC to the internet without opening any web browsers, P2Ps, messengers and such.
Is there still a possibility that I can get virus or other malwares?
In my opinion,nope but the hacker will track you.
Yes.
If you connect your PC to the Internet and do nothing then might as well not do so. If you connect your PC to the network then just about anything you do to download data to your system (program updates, email and even functions seeking to connect your system) has the potential to bring harmful data into your system.
That’s why firewalls and antivirus products exist.
Use a firewall and ensure all web-facing applications are secure:
PCs Infected in 12 Minutes:
http://www.realtechnews.com/posts/1511
Hi YoKenny,
Well, if you connect to the Internet default, with full rights, and without a Firewall or adequate AV solution, the infections come in harder and faster than you can hose them out. Remember malware already has overgrown the Internet, you need protection. And most malware, especially spyware, adware and trackware sits silently in the background until you activate it, then in the end your machine is so slow it is unworkable for you. People that come here want to do something about this, and we gladly help and inform, but alas a lot of the not so intelligent uneducated users that only use a computer to click away at - and completely without a notion what they are doing - dump their computer to buy a new one, apart from that they pose a threat to others with their malware spewing machines or as part of a zombie bot net infecting others… The level of malware awareness for common users has never been so low as now and here in the days of the dumbed down masses, “give them some technique and they will not notice they’re slaves-age”, sad but true…
polonus
just few time ago a friend of mine brought me some documents for school with his USB-stick and when he connected it to my computer avast immediately alarmed me that a virus has been found in the system32 folder - and every times i connected the usb-stick again the same virus was found at the same place… (also when i tested it on other computers…)
so the virus tried to install itself from the USB-device onto my computer but avast stopped it! 
big thanks to avast! 
yours
onlysomeone
Welcome to the forums, randomkill.
As others have stated above, your computer can be infected without you personally downloading anything while connected to the interent.
And, your computer can be infected without even being connected to the internet as onlysomeone explains in his example above.
imo
Hi, 
imo no, provided you are behind a router or at the very minimum have windows firewall on.
What are you doing on-line then? Just seeing emails?
Exactly what i was thinking, why would you even need to be connected to the internet then ? ???
I do online gaming a lot and I usually shut down all the firewalls and securities as I logged to my gaming profile because they sometimes lagging my online performance.
Does playing games online give you virus too?
Yes, most certainly you can get a virus playing on-line games. If you have taken the above actions more than once, your computer is probably infected with some type of malware.
Qoute from YoKenny above:
PCs Infected in 12 Minutes: http://www.realtechnews.com/posts/1511
Sure, a very common infection way…
You shouldn’t disable the antivirus and the firewall.
If you need better performance, you need a better computer… sorry, at least, more RAM.