Can virus/program/ anything stay after a full reformat?

[vox345]

Suppose: I have a computer. I connect it to the internet to update windows, download some programs, etc, then disconnect it from the internet and never hook the internet back up until after I do a full reformat of windows. Could any sort of Trojan/virus/malware/hack programs etc be attached to the computer during the time it had internet and still be on it to relay info after it was fully reformatted and connected to the internet again?
Thanks.

 

[cboucher]

A full format will most likely get rid of anything harmful. If you're worried about it, there are programs out there that do a secure erase, meaning that all areas of the drive are erased and then written to, ensuring all data is destroyed.

 

[MMM]

Suppose: I have a computer. I connect it to the internet to update windows, download some programs, etc, then disconnect it from the internet and never hook the internet back up until after I do a full reformat of windows. Could any sort of Trojan/virus/malware/hack programs etc be attached to the computer during the time it had internet and still be on it to relay info after it was fully reformatted and connected to the internet again?
Thanks.

Yes they can, only if the virus has affected the Master Boot Sector.
In these cases you need to contact the hard drive manufacturer for a utility disc tools which will have a program to restore the MBS.
These tools can usually be downloaded from the hard drive manufacturers web pages.