How do I get into task manager and my computer?

Her computer is infected with several viruses, you can't open task manager any way. When I open the start menu, there is no programs, just an internet exploder icon. Pop ups bombard her computer with no option to close them out. I am running a boot time scan with Avast but forgot to turn system restore off first, but every virus I am finding won't allow me to repair, or move to chest only delete. I am without system restore disk so I don't want to wipe and go, what should I do?