you can try starting in safe mode with networking, install professional anti virus from a disk, such as Norton or panda, which will scan upon installation, activate update and scan again...
you can try safe mode w networking, download and install malware bytes, update and scan, as aford has recommended.
you can connect w safe mode networking to panda active scan, although I think they may charge you a fee.
you can remove the drive, install as a second drive on a working computer, recover and backup your personal files, reinstall the bad drive, reformat and do a fresh install of operating system, drivers.
you can have a computer shop do any of the above for you...