Q: system crash !!! Pl... Help !

Uninstall AVG and MacKeeper to start with.

https://support.avg.com/SupportArticleView?l=en_US&urlName=How-to-uninstall-AVG- AntiVirus-for-Mac

how do i get rid of mackeeper app that has somehow downloaded on my computer

Do not install MacKeeper

The

Run this and post the results here so we know more about your configuration.

http://etrecheck.com/

EtreCheck

https://discussions.apple.com/docs/DOC-6172

Determine if the same problems occur in "Safe Mode": Try safe mode if your Mac doesn't finish starting up - Apple Support

I used the AGV Cleaner and it said 0 error The same result as the Mackeeper

Those programs will only cause trouble. Uninstall them according to their respective instructions.

"AVG" may prove difficult to remove. When I evaluated that product I determined its uninstallation instructions did not work. I resorted to completely erasing the Mac on which it was tested. If you have a Time Machine backup preceding the installation of those products I recommend you restore that backup.