Follow some or all of these steps to insure safety on your network or PC. This is for viruses only. If you'd like to find information concerning Trojans, Data Miners and other Spam prevention, please visit this post.
1) Preventative Maintenence
a) Purchase a REAL TIME anti-virus solution from a major vendor. Wether it be McAfee, Norton (Symantec), Trend Micro or Sophos, it's worth the little money it costs to get a 1 year subscription. Keep your virus definitions up to date with the vendor that you purchase your virus definitions from.
b) Schedule, at the least, weekly virus scans on your network or personal computer. You really should be praticing this procedure more than once a week, but this is a bare minimum.
c) Keep open folder and drive shares to a minimum. One of the first things that most viruses try to do is replicate itself. Stop damage to your LAN by minimizing the number or network shares that you have connections to and/or available.
d) Keep anonymous downloads to a minimum. Most of you share/receive files over some sort of P-2-P file-sharing application. Some of these files, although they appear to be ok, are really viruses just waiting to be opened. What's the first thing that you do after downloading that new Metallica song?????? Well, try and play it of course.....people KNOW this!
2) Actions to Take
So, what happens if you are infected?????
a) If you are present an notice that your PC is infected, the first thing that you should do is disconnect from your LAN immediately! I've seen people infected with viruses and on here asking for help. I understand why but as a precautionary measure on a LAN, disconnect from your network right away. This will minimize potential immediate infections on other PCs on the same LAN. Whatever you have to do.....do it fast: Disable your LAN, unplug the LAN, turn off the switch, turn off the gateway/router,, whatever it takes.
b) For those with a second computer to help you out, try and find out as much as possible about the virus that you are dealing with. A lot of information can be found at your particular vendor's site. A lot of these sites have removal tools as well.
c) Run a search on google.com concerning your virus. It's absolutely amazing what you might find!
This should get you started.