In Firefox 3.6.13, when intending to open a website, an empty page with the words in the upper right hand corner "skip this screen" would come up. Reloading the same page would make disappear this message. My research resulted in the fact that this was caused by a malignous software called "Contextual Tool Yourprofitclub" that installed itself without my consent. De-installing this program (one has to reconfirm a code - see attachment) solved the problem with the nagging screen. I had done a complete scan before with Malwarebytes Antimalware, it however didn't report any anomaly. Why does Malwarebytes Antimalware not recognize this malware? Did confirming the code probably leave some traces on my system?