How come? Isn't CCleaner supposed to get rid of the unnecessary stuff kept on your mac
CCleaner and lots of other similar apps make a lot of money by convincing people that there's "unwanted" stuff on their Mac that is slowing things down. In SOME cases, there might be, but it's not something a fresh install won't fix. And in the majority of cases, CCleaner and similar apps aren't helping, and may actually hurt performance.
Your new MacBook Pro is unlikely to have anything on it so soon that would wreck your performance... UNLESS you installed a bunch of gunky "optimization" programs.
I would suggest backing up your files, and doing a fresh install of the OS and software (not from a Time Machine Backup), and then avoid installing any "cleaner" programs.
Chrome is also a huge resource hog and not worth using at this point.
and AVG from me getting a virus?
Malware exists on Macs, but there is already built-in OS security that does a good job of helping you avoid it. The stuff that
can hurt you on a Mac does so largely by convincing the user that it's a legitimate program and that you should grant administrator privileges to install it. If the malware manages to convince you to give it the keys to the castle, then no antivirus software is going to help you.
Bottom line: AVG running constant scans is robbing your Mac of resources, and probably won't be much help to you anyway.