<p>I need to write some registration data (unique computer number, and corresponding activation code).</p>

<p>The Computer Number needs to be visible from <i>other</i> programs and <em>all</em> accounts ({Admin|Non Admin} with User Access Control turned {On|Off} )</p>

<p>It's acceptable to write the Computer Number and Activation Code only from an Admin account, but it needs to be readable from any of the other accounts. </p>

<p>Currently (and I need to test this more) it seems that  if the the CN and Activation Code are written with UAC off then when the user switches UAC ON the Computer Number isn't visible.</p>

Yes, but 234 won't be stored in the cookie. The cookie will only contain a unique ID (for example,
```
lit3py55t21z5v55vlm25s55
```
). Every time ASP.NET sees that unique ID, it will look up the corresponding session information.
If you don't want to use cookies, you can put the session ID in the URL. Read this
MSDN article's
section on Cookieless SessionIDs.