I had a Norton antivirus that came along with the laptop when i bought it but it has expired so i removed/uninstall it and tried to replace it with AVG but I wasnt able to do so due to the error that says i already have an antivirus and i should remove it first before installing a new one. But i already removed the norton and there's no other AV installed in it. I only have windows defender but its just a spyware right?..
another question, is it ok to have another spyware aside from windows defender?
Try uninstalling again using the norton disk in the administrator account.
You can have more than 1 anti spyware running but I would not bother. Running a spyware checker once a week on all files should suffice, if you have a spyware checker running all the time in the back ground. Use a different spyware checker to scan all files from the one you use all the time. This is because different spyware checkers have different levels of protection. I would recommend spybot search and distroy.