DNS or WinInt

I seem to be having issues with my internet connection. I've been getting messages stating that the DNS lookup has failed. Also Outlook Express crashes when I close it without first being connected via dial-up. Sometimes the mail cannot be sent on Outlook Express but I can receive mail. I have contacted my ISP and they seem to think something is altered in either the DNS or the WinInt file. I don't have a clue.

This started up when I installed Earthlink, but have removed it from my machine. Now I only have the one dial-up service provider. But most everything that deals with the internet still isn't working right. Which also includes the WUHU (Weather Underground Heavy Weather) Uploader tool.

The uploader tool won't upload current and recorded data to Weather Underground, but it is to CWOP (citizen weather observer program).