Easiest would be getting yourself a gamepad and then using Xpadder to map the controls to it...but without that option you're stuck to remembering keys for buttons and definitely no mouse use.

I personally always have it setup as Z= B, X=A, A=Select, S=Start, Q=L, W=R which I always found fairly simple to use.

 

You can't use the mouse, but you can change the required key for each button to whatever you want by going to Options->Joypad->Configure->1. If memorizing that is too hard, you can always change it to A=A, B=B, and so on. It's inconvenient for your fingers, but it's definitely not hard to remember.

My current setup:
A=X
B=Z
L=A
R=S
Start=Enter
Select=Right Shift
It's not too hard to remember for me. I hope this helped.

 

I have an Xbox 360 (with wireless controllers), so I spent $20 on a USB adapter. It's recognized automagically in Windows Vista and Windows 7, and pairing works just the same as with the Xbox 360. I've purchased other game controllers over the years, but the Xbox 360 controller is by far my favorite.

 

Configure

All I do is go to options, joypad, configure, 1 and set up my own. What I use is wasd keys for movement,
numpad 4 and 6 for a and b.
numpad 7 and 9 for left and right pads,
numpad 5 for select,
and space for start.