What is Microsoft.NET Framework Assistant 1.1?

It’s something that allows web sites to install stuff (without asking your permission). You only need it if you need any of those sites to install stuff, and they don’t provide another way to install it, so you probably do not need it.

Since you have version 1.1, you should be able to uninstall it from Firefox. (If you had version 1.0, you would have needed to uninstall it in the Windows Registry, which could be a problem if you did it incorrectly.)

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