No.
The infect your computer by being undetected by your anti virus and posing as a harmless file.
No.
infect it
Yes, any thing that contains software and connects to your computer, that is infected, can and will infect it
Get yourself a good antivirus.
Virus and worms.
You can tell by the viruses and spyware that infect your computer
If a virus was burned to the DVD, then yes, this can infect a computer.
most likely
No.
300,000
Adware can be spread from the second it's on your computer just by being there. Because it is on your computer, it can secretely infect every program on your computer, allowing it to infect everything in the system once you open one of the infected programs.