You have a virus infection, u need a bootdisk from Avira called rescue system to be found on their site google avira rescue cd and dowload from site and burn to cd, then boot cd this will scan and repair your system, you must tick the boxes, repair files rename files, this renames any and all virus's found, when scan completed remove cd and reboot, you should now be able to access net and download malwarebytes antimalware, update this and scan and keep scanning it cud take several scans to clean ur system.
you will need a freind to obtain the boot cd file as ur unable to connect to net urself.
Bob Macdonald, March 2010
