Is it possible for a virus to change the BIOS? a while ago i revcieved a virus and in the end had to re format my hard drive, when i installed the O/S etc again i found that the virus was still there. i have been given several reasons for why the virus may still have been there but i am unsure to which one is right!

1)You didnt actually reformat the pc properly and installed the O/S over the top (doubt it!)

2)Hard drives dont fully get cleaned with one format, it needs to be done several times

3)There maybe a bot with my IP taged so that evertime i connect to the internet a bot starts a chain of attacks on my computer

4)My BIOS has been altered!