Simply change this key to 1
HKLM\SOFTWARE\TrendMicro\PC-cillinNTCorp\CurrentVersion\Misc.\Allow Uninstall = 0 original key
HKLM\SOFTWARE\TrendMicro\PC-cillinNTCorp\CurrentVersion\Misc.\Allow Uninstall = 1
new key
Simply change this key to 1
HKLM\SOFTWARE\TrendMicro\PC-cillinNTCorp\CurrentVersion\Misc.\Allow Uninstall = 0 original key
HKLM\SOFTWARE\TrendMicro\PC-cillinNTCorp\CurrentVersion\Misc.\Allow Uninstall = 1
new key