Defrag and Dialup networking

you didn't mention you os...
1) how about running defrag thru the task scheduler. you can set username and password in there to run as any user...or spring for corporate version of diskkeeper...
2)right-click on the connection, get properties...

From Technet:

The only way a non-administrator can defragment a local volume is to run the Dfrg.msc console in the context of a user who has administrator privileges. You can accomplish this by running the following command:
runas /user:administrator@domain.company.com "mmc dfrg.msc"

An administrator can log in and reset the Allowed Actions in the Policy Settings for the User Group or reset the Approved Users to use the Defrag execution files on that files security settings.
The Policy concerned is usually called 'Perform Volume Maintenance Tasks'.

I rarely use the default group actions that come with MS Windows, I find it better to create a set of groups to suit the organisation and then just put people in my groups and disable the default groups. This has the added benefit of making it harder for unauthorised people to gain privileges once they get in.