Guild Wars 2

I had i5 2.80Ghz and GTX 650 (non-ti) on a 1920 × 1080 resolution, can I run at least all on medium? And what will be the FPS?

Yes. A 650 non ti isnt great tbh but it should manage medium, if it was a 650ti probably medium/high.
FPS should be around 30-40, possibly more depending on settings.

If you CPU is a K class then it can be OC’d, try(if you have good air cooling) to get it close to 4.5ghz. If its not k class then you will have issues in WvWvW. FPS will likely drop below 20 in medium – large fights, however this may not be caused by your CPU to start with as your GPU will likely slow you down with so many effects to render.. lowering all settings to low would remedy this but then you fps would be capped by your CPU.