With the biggest news in a decade dominating the Internet, it didn’t take long for rogue viruses, Trojans and other malware to mess with computers given the chance. Web searches and links to a variety of stories — real and fake — about the death of Osama Bin Laden are sprouting with all kinds of malicious software as cybercriminals look for a big payday tied to the appetite for news about the Al-Qaida leader’s demise.