A 71-year-old Taunton man was arrested Wednesday for allegedly possessing 998 computer files with pornographic images of children as young as 5 years old, Raynham police said. Guy C. Davis, Jr. had taken his computer to a Raynham store for repair, and on Oct. 25, a technician discovered sexual images of children, said Raynham Police Chief James Donovan. The store, CTS Computers, called the police and handed the computer over to officers. Donovan said police later obtained a search warrant for Davis’s apartment, and found at least 10 unsecured firearms. “He was licensed to have them, but you need to have them locked or triggerlocked and secured in Massachusetts,” said Donovan. Davis was arraigned Thursday on one count of child pornography and 10 counts of improper storage of firearms, Donovan said, and a not guilty plea was entered on his behalf.