If you want to stop using Hyper Terminal as your default telnet client, you need to modify your registry file. To perform this procedure, you must be a member of the Administrators group on the local computer, or you must have been delegated the appropriate authority. If the computer is joined to a domain, members of the Domain Admins group might be able to perform this procedure. As a security best practice, consider using Run as to perform this procedure.
The following steps can help you determine if HyperTerminal has been set as the default Telnet client and show you how to un-register it.
2. When DOS window popped up and type regedit, and click OK.
3. Registry window popped up and from the left panel, locate the following registry key;
4. Now, in the right panel, locate the registry entry:
5. If found, right-click on this entry and choose Modify. And modify the value to:
6. In the left panel, locate the following registry key:
7. In the right panel, locate and delte the following registry entry:
8. Modify it to below