Q. Does each user have to logon on to their account and repeat the Windows Updates and PC Maintenance/Defrag processes?
No. Changes to the hard drive affect the disk, not users.
I have read some info says that you have to be logged on as the Administrator to install programs and some info says that regular User's can install most but not all programs.
Correct. System administrators must be logged in to install some programs. Limited users cannot. If you aren't sure which you are, go to Start > Control Panel > User Accounts. If you're an admin, you can do anything on the computer. If you're limited, you're... limited.
I wonder if our user accounts have more rights then they should because we are all able to download and install programs from the internet.
Indeed, that is a danger. However, it's the Admin's job to make sure the computers don't contract a virus. If a user offends the PC by contracting a lot of viruses, the admin can change the password for a while.
Q. Is there a way I can see if all our accounts should be able to do this?
The start > control panel > user accounts shows who has admin priveleges and who doesn't.
Q. Also, when installing new programs are they always available to each and every user's account?
Some. You may be able to choose to install only for yourself, if there are multiple users. However, by default all users can access the programs you install.
I ask this because my son downloaded a program called Bear Share something or other from the internet that I believe has caused advertising pop-ups while I am browsing the internet and logged into my user account.
Make sure you have an Anti-Virus application.
This Post may be of use to you.
Q. While logged in to your own account, is there a way you can you avoid the negative effects of programs that your kids want to use?
What kind of "negative effects"?
I recently installed a virus program and spyware remover from the internet and would like these programs to scan all the files on the computer.
Without knowing which one, I can't tell you how to do it.
Q. Does each user have to logon on to their account and repeat the virus and spyware scanning processes?
No. Again, you're affecting files, not users.