Run a scan with the Kaspersky online scanner and post the results here and we can give you some feedback about the ‘objects’ found: they may not represent any real threat, but without knowing what they are, it’s impossible to comment.
You can use more antiviruses together if one is active (real-time) and others are not (only on-demand).
There can also be two or more active if you configure them properly (and know their strenghts and weaknesses) so they actually compliment each other. For novice users it’s recommended to use just one active antivirus.
I would say that a conflict at low level will occur, sooner or later, when you uninstall one of them and try to install another, both of them fighting to be the owner of a scanning (of an email, etc.), incompatibilities of services…
Of course, the instability is a way of life for us, beta testers, the ones who want to live dangerously… and for the second we’re living 8)