AVG and/or CCleaner?

Hi,

Are AVG and CCleaner the same sort of thing or can I have both of them?

I'm asking as my laptop is a bit on the slow side and my wife might have to work from home so I'm trying to sort it out for her.

I've uninstalled quite a few programs and things we can do without for a few weeks.

Just to add, I've already got AVG installed and was wondering if I can add CCleaner to get rid of any files that aren't needed.

Thanks,
Dave