Using Administrative Account

I'm sorry if this info is somewhere else but I can't find it. I have an admin. account as well as a guest account on my compaq laptop, running XP Home SP3. The guest account is just precautionary, I am the owner/admin, but browse on the guest account.
My problem I don't know how to add plug-ins to Firefox or add downloads to the guest account. When I download them in the admin account they don't show up in the guest account. The guest account won't let me install the downloads.
If I save installations to the shared folder, doesn't that defeat the purpose of keeping a guest account in the first place?

 

guest account

here are MS reasons for guest account limitations. they set it up like that, I don't think there is a work around

 

Thanks. My daughter just got in on this and suggested if I get a download to my guest account, I can right-click the installation file and select "Run as..." and after entering my password, install it under the admin account's authority.