Guru Nanak Dev Ji (tere dost lagdey ney, satkaar naal nahee bulaa sakda?) has mentioned the Quran in gurbani just like the `vedas.` we`ve already been through this just do a search on the forum.
I will quote.
Mihar maseeth sidhak musalaa hak halaal kuraan.
Saran sunanth seel rojaa hohu musalmaan.
Let mercy be your mosque, faith your prayer-mat, and honest living your Koran.
Make modesty your circumcision, and good conduct your fast. In this way you shall be a true Musulmaan.
Guru Nanak Dev Ji Raag Maajh Ang 140

So now are you going to say Sikhism has influences from that?  Was Hinduism a religion right from the begining? What about Christianity?

You wanna tell me what Hinduism is again? I dont wanna put down anything but saying Sikhi is something else really doesnt make me happy. I will quote.

In 1995, Chief Justice P.B. Gajendragadkar was quoted in an Indian Supreme Court ruling.

"When we think of hte Hindu religion, we find it difficult, if not impossible, to define Hindu religion or even adequately describe it. Unlike other religions in the world, the Hindu religion does not claim any one prophet; it does not worship any one God; it does not subscribe to any one dogma; it does not believe in any one philosophic concept; it does not follow any one set of religious rites or perfromances, in fact it does not appear to satisfy the narrow traditional features of any religion of creed. It may broadly be described as a way of life and nothing more."
Thus some scholars argue that Hinduism is not a religion per say  but rather a reification of a diverse set of traditions and practices by scholars who constitued a unified system and arbitrarily labeled it Hinduism.

I got that from the wikipedia definition of `Hindu` and its all cited so u can see the sources.