Mac mini not run on 2gb memory?

Post a screen shot of the pocesses running. Sort it so the ones that use the most CPU are at the top. It may be that a process is slowing down the Mini

Look at the bottom of first Activity Monitor screen you posted. There is a yellow band labeled Memory Pressure. The yellow color indicates the system is likely to "page" memory out to the swapfiles on the hard drive and at the same time likely to be "paging" back into memory from the swapfile. That is a major slowdown and the primary cure for that is additional RAM. Ideally you want the Memory Pressure to be green which indicates you have enough memory that it is unlikely you will be paging out or in. If that band turns red then you seriously need more RAM because that would indicate you are almost constantly paging out and in.