What is the relation between Nirvana and Parinirvana?

We all are combination of the body, the mind and the self. Total liberation from the death and the rebirth is attained when the self manifests as supreme happiness, the mind manifests as light of knowlidge, and the body manifests as a positive namkarma. This is moksha. Nirvana is attained when the body self destructs itself into pure matter after a predetermined life span. If transformation of the human mind into light of knowledge is called nirvana, then self destruction of the body or the sense mind would be called parinirvana. There is lot of similarity between jainism and buddhism.

Just as the light and heat of the sunlight are inseparable, liberation or moksha and nirvana are inseparable. The delusion that I exist, and the ignorance that I am this bodily existence are inseparable. The NOBLE TRUTH that all beings are without independent self existence, and the NOBLE WISDOM that all things are without self nature are inseparable. Buddha talks about the ONE VEHICLE, which transcends both the small and big vehicles. If viewed from the right perspective, both jainism and buddhism talk about NIRVANA while alive. Parinirvana is attained when the human body self disintegrates by itself when the last breath is exhausted.

Nirvana = ending all rebirths by attaining enlightenment

Parinirwana = physical death of a person who has achieved Nirvana

Parinirvana is the nirvana that occurs after death. You are no longer reborn in any of the 31 Planes of Existence Parinirvana is not a place. The Buddha said what nibbana is not

There is that dimension where there is neither earth, nor water, nor fire, nor wind; neither dimension of the infinitude of space, nor dimension of the infinitude of consciousness, nor dimension of nothingness, nor dimension of neither perception nor non-perception; neither this world, nor the next world, nor sun, nor moon. And there, I say, there is neither coming, nor going, nor stasis; neither passing away nor arising: without stance, without foundation, without support [mental object]. This, just this, is the end of stress. - (Udana 80)

Here is what the Buddha said it is

This is peace, this is exquisite — the resolution of all fabrications, the relinquishment of all acquisitions, the ending of craving; dispassion; cessation; Nibbana. - (Anguttara Nikaya 3.32)

Entering Parinirvana after death is not a rebirth, nor a place.

• Is it not somewhat contradictory?

  Well I guess it's difficult to understand, partly because it's an uncommon experience (there are some people who live in the tropics, and to whom it would be difficult to explain "cold" or "snow").

• If Nirvana means the end of rebirth ...

  I think of Nirvana as related to the 2nd and 3rd noble truths (i.e. that "suffering is caused by craving" and that "suffering and craving can end").

  Nirvāṇa (Sanskrit: निर्वाण nirvāna ; Pali: निब्बान nibbāna ; Prakrit: णिव्वाण ṇivvāṇa ) literally means "blown out", as in a candle. It is most commonly associated with Buddhism. In the Buddhist context nirvana refers to the imperturbable stillness of mind after the fires of desire, aversion, and delusion have been finally extinguished.

  When you see a flame, the flame appears to 'cling to' or to be 'attached to' whatever is fuelling it.

  A fire "goes out" when it is "unbound" from its fuel.

  When an arahant or Buddha attains nirvana in this life, then they remain "unbound" for the rest of their life and are not subject to further rebirth. So it's true that after nirvanna there is no further rebirth, but nirvanna doesn't mean "no rebirth", it means "unbinding" (i.e. "no rebirth" is a consequence of nirvanna, not the meaning of it).

• ... and rebirth means the evolution of consciousness ...

  Well I think that "rebirth" literally means physical "birth": i.e. a consciousness embodied in an embryo that's subsequently born as an infant etc. Assuming you're already human, being born again is not a prerequisite to consciousness.

• ... did the Buddha possess no consciousness during the last 45 years of his life?

  That's not so:

  • For example the Buddha remained able to see (mundane sight) which implies "eye-consciousness"; and the same for the various other senses.
  • The Buddha is also said to have developed extraordinary powers of consciousness (e.g. being able to remember previous lives, being aware of the karmic state of other people, etc.).
  • The Buddha attained meditative states, called "The Jhanas" (which were also a type of meditation which he used while his body was dying)

  Apart from the above there's something else unusual about his consciousness: which is that it's described as having no effluent (no āsava)

• What is the relation between Nirvana and Parinirvana?

  I think pari means "total": Parinirvana means "total nirvana" or "total unbinding". It implies the unbinding of the body, physical death.

What the Buddha experienced at 35 was called sa-upādisesa-nibbāna - nirvana with remainder. What he experienced at 80 was called anupādisesa-nibbāna - nirvana without remainder:

“dvemā, bhikkhave, nibbānadhātuyo. katame dve? saupādisesā ca nibbānadhātu, anupādisesā ca nibbānadhātu.

There are these two, monks, elements of nibbāna. What two? The element of nibbāna with remainder and the element of nibbāna without remainder.

-- Iti. 44

The difference is that after the former, there is still sequences of physical and mental formations that continue as a consequence of the birth of the being and have to work themselves out, which they do at the latter, signifying an end to all such physical and mental formations.

The actual experience of nirvana during the former (which can last from a few moments up to seven days) and the latter (which, due to there being no remaining sequence of formations and no craving to create new ones, is permanent) is the same.