arena chess engine

Welcome :)

In the engine settings (engines > manage > Details > special), it has an option to change CPU usage. The less it uses, the weaker it plays (and the less strain on your system), so see what works for you.

I have no idea why it flips the board on you though

For one, Arena is not a Chess engine, but just a graphical user interface. (A program that draws a chessboard on your display, like WinBoard or Shredder.) It cannot think up moves, and is dependent on external programs for that, called 'engines'.

So how strong it plays completely depends on what engine you use. There are more than 500 engines that can run under Arena, most of them available for free download. (There is an overview on the Arena website.) They range in strength from 3300 Elo (Houdini running on 4 cores) to below 0 Elo (e.g. Pos 1.19, Brutus Random). So it should be easy to find an engine that plays around the level that you like, and fine-tune it by giving it time odds.

For instance Fairy-Max is an engine that is certainly beatable by a club player, if he can keep focused. For this reason I included it is included with WinBoard as a sparring partner. (Also because it plays many of the variants supported by WinBoard.)