Sometimes I get this question and it's an expired antivirus that is blocking the internet (for your protection.) I uninstall the thuggish suite and it gets online.
More bootable, no internet scanners at https://www.lifewire.com/free-bootable-antivirus-tools-2625785
I have a windows vista laptop which I suspect has a virus that is preventing me from going online. Is there any antivirus available which works *without* needing to go online initially?