DavidR
2
avast doesn’t remove anything without user input and first it must have detected something.
What is the infected file name, where was it found e.g. (C:\windows\system32\infected-file-name.xxx) ?
Check the avast! Log Viewer (right click the avast icon), Warning section, this contains information on all avast detections.
What you are seeing is rogue ware trying to convince you to visit a site or download a patch/software (probably at cost) to resolve the problem. I strongly doubt it has anything to do with the Security Center and control panel may have been disabled by malware.
A new tool RogueRemover, available here http://www.malwarebytes.org/rogueremover.php, download this and run it, then try one of the others below and report your findings.
If you haven’t already got this software (freeware), download, install, update and run it, preferably in safe mode.
If using winXP AVG anti-spyware (formerly Ewido). Or SUPERantispyware Or Spyware Terminator.