This is slowing down my computer.

The friendly way: BTW. These instructions are for use with the "Advanced View" of BOINC, selectable via the "View" link near the top left of the BOINC Manager screen. First off, click the "Suspend" button, after highlighting "Einstein@Home" on the portion of the Manager screen. On the "Projects" tab of the BOINC Manager, click the "Update" button after highlighting "Einstein@Home" (just click on it) in the main screen. This will report to the project server any tasks you have finished. After a few seconds, allowing time for the report, click on the "Tasks" tab. Hold down on the Ctrl key and highlight all of the tasks by clicking on each one. Then click on the "Abort" tab. This will present you with a series of pop up boxes that will ask for confirmation on the abortion of each task. Click "Yes" on each one. Then click the aforementioned "Update" button again. After this is done, uninstall BOINC with your Vista OS Control Panel through "Programs and Features".

The unfriendly way: ...skip down to the last sentence of the above paragraph and follow through. But that would be kind of disrespectful to the other participants that are working on the same work units that you have/had, because they would have to wait for your unreported work units to time out and then be reissued to other participants.

AFAIK, the accounts can't be deleted, but you can blank out your profile (if you have one), change your name to something different, hide your computers and change the email to something nonsensical. Out of sight, out of mind.