How to deal with annoying 3721 !?

Someone told me this morning that "C:/winnt/Downloaded Program Files
Set it to read-only, and 3721 won't be recruited !", Oh. I tried it. It seems useless. It's annoying. I deleted it and deleted it again. It's really inexplicable. Who is it !?

However, it is found that if you visit a website with a 3721 plug-in, it will prompt whether to install the Website, you must click "no". It cannot be installed. Anyone has a trick. Please refer to it! In fact, there are always many prompt boxes indicating whether to trust the Internet. At this time, you only need to carefully check the instructions to avoid such troubles. It is because you are used to clicking "yes". Generally, you don't pay attention to its prompts ......

I started to do things at work.