[pogo]

Can someone explain the difference between these:

ganar
a ganar
de ganar

I keep seeing them in Spanish sentences and i'm not sure what the difference is particularly between the first two, for example what would be the difference between

Qué vienes a buscar?

and

Qué vienes buscar?

Am i right in thinking you'd use de + verb infinitive when it's followed by a noun such as oportunidad de ganar.

thanks for any help.