Dial up connection problem

I currently have a HP Laptop, with a XP windows operating system. I was using a Lan to connect for over a year and now I want to use a dial up.
When I try to connect using a dial up, a pop up box says the following ” Operator Assisted or Manual Dial, Pick up handset and dial or ask Operator to dial. Press Ok Immediately after dialing, then replace the handset. Phone number xxx xxx xxxx ok”.
I may have messed up the settings of the modem or something, this is driving me crazy and I’d love to fix it. Thanks for any help