How Run Inactive Users Script

[NeedIt]

I've got an SMF 2.0 forum that is now running painfully slow.  I am wondering if it possibly has to do with Inactive Users.  I'm not sure I totally understand but this thread

http://www.simplemachines.org/community/index.php?P=902819458f82fc917fa6d8e91a4cc994&topic=293441.0

recommends running this script here:

"Run the mark read for inactive users script periodically. The log_topics, log_boards, and log_mark_read tables are not the best designs, and for some unlucky folks end up dominating their database. Pruning them can help.."

My problem is this:  I do not have admin access to my site since I am shared hosting. 

So how can I clear out inactive users?

[ApplianceJunk]

Could you post a link to your forum?

[NeedIt]

I forgot to mention that this is all on Windows.

[Colin]

Is this topic solved as indicated or do you still require further assistance?

[NeedIt]

Is this topic solved as indicated or do you still require further assistance?

No, I still don't know how to do it.

[Colin]

Alright.

What do you mean by...

I do not have admin access to my site since I am shared hosting. 

You don't have root access obviously, but you administrative access, right?