Hi,
I’m Dyari. Thanks for reaching out.
Cloudflare is a security service used by many websites. You do not need to sign up for it, and seeing a Cloudflare blocking page does not necessarily mean that a program has been installed on your computer.
Does this happen on all websites or only one specific website? Does it happen in all browsers? Also, please check whether an application named Cloudflare WARP or 1.1.1.1 is installed on your device.
If possible, please share a screenshot of the blocking page, including any error code or Cloudflare Ray ID. Please hide any personal information.