You can add/remove dial-up networking. But missing is NOT a bad thing. You didn't write in your post what was broken, so my response is to not fix it.

In most of my posts I mention that newer spyware corrupts the Layered Service Provider. Removing the spyware may cause loss of internet connectivity. This isn't the fault of spyware removal programs but the spyware that damaged the LSP. Find LSPFIX with GOOGLE to fix that issue (which is not your DUN issue, but may be related.)

Again, no mention that you use a modem or DUN...

Bob