What would have been *appropriate* would have been for you to give
complete
details about your question so all these good people wouldn't have had to
waste lots of time guessing.
Please review at least some of the information at these links for future
postings so we can avoid this sort of thing again.
http://www.elephantboycomputers.com/page2.html#Usenet
http://support.microsoft.com/default.aspx/kb/555375 - How to Ask a
Question
http://users.tpg.com.au/bzyhjr/liszt.htm - How Not to Get Technical Help
on
Usenet
Yes of course you can get malware from the Internet if your computer is
not
properly protected. If by "no extra software" you mean no antivirus
program, you are particularly vulnerable, particularly if you are not
behind a router.
If you are talking about a computer that is just *sitting* there and not
running any programs and is behind a router, then it's pretty safe because
you're not *using* it. Start using it in that shape and all bets are off.
All talk about antivirus and firewalls aside, the single biggest factor in
whether you get infected is YOU. If the end user doesn't practice "Safe
Hex", no amount of security software will protect him.
Here are various sites that will show you how to stay safe and answer your
questions about security in depth. Additionally, as you continue to
research this on your own, use Google to find even more security-related
sites that may go into the detail you want.
http://www.getsafeonline.org/
https://www.mysecurecyberspace.com/
http://www.getnetwise.org/
http://wiki.castlecops.com/Malware_Removal_and_Prevention:_Introduction
http://www.claymania.com/safe-hex.html
http://www.aumha.org/a/parasite.htm - The Parasite Fight
http://msmvps.com/blogs/harrywaldron/archive/2006/02/05/82584.aspx - MVP
Harry Waldron - The Family PC - How to stay safe on the Internet
Malke