If all humans aren't eradicated by nuclear war, I don't see why all memory, books, hard drives, other archives, computers, power plants, machinery, or even all contraceptives would be.
Whatever technological knowledge survives in the books, most of it will be useless for centuries, as we regress into pre-industrial level of technology and can't climb back out - we've already mined out all easily-accessible high-density energy sources that are necessary for reindustrialization.
Simple computers are relatively easy to make with today tech. Software exists already.
Nor is there a particular shortage of hydrocarbons to burn, with consumption reduced so much due to population loss and reduction in quality of life. Consider that US today emits more than 200x carbon into the atmosphere than it did in 1850, and that this growth has been exponential. So what we consider one year worth of reserves today, could provide energy for many decades in this hypothetical.