System Restore error

[Cheryl]

My computer was infected with Lovsan worm. I have
removed the worm, but have after-effects. My search
function in not working. It refers to a search companion
file missing. When I check on how to correct that, I see
that I should backup the Registry before I edit it. When
I go to System Restore, I get a message that says that
System Restore is unable to protect my computer and that
I should restart and try to run it again. I do that, but
it still doesn't work. Help!!