nor which Operating System you are using, so it is impossible to give detailed answers.
Here's a generic answer to the low disk space problem. If this is Windows XP disable System Restore, then re-enable it. This will delete all the System Restore back up files, but only do this if your system is otherwise working well.
Your second problem. You should also have Internet Explorer on your account. Did you check the Start Menu?
If nothing is there, find the shortcut from one of the other accounts, and drag it to the All Users Start Menu folder.
I get low disk space warning, I click on it to fix problem as I have done in the past. It usually fails to clear up the recommended 200 mb so I go to add/remove programs as instructed to delete some programs and find enough to satisfy need. This time I go add/remove and there's hardly anything left on there to delete. It's all essential to my use. As a matter of fact that adding up all the space that is there, if deleted would barely cover the recommended 200. Also my wife and son have Internet Explorer on their user accounts but I noticed that it is not showing on my programs list!!! Please help.