Suspicious.Cloud.7.L

Every time I turn on my computer, I get the warning that this HIGH threat Suspicious.Cloud.7.L hasn't been removed.  I use the Norton Power Eraser & it doesn't get rid of it.  Isn't that why I pay Norton an annual fee to keep these things away?  I have Norton by Symnatec Antivirus protection.  How can I get rid of this?  What does this threat do to your computer?