I'm going to say "no", assuming that when you say "computer", you mean transistor-based.
I am not an expert on the subject, but I suspect making a facility that can manufacture thousands or millions of transistors, and then operating that facility would take obscenely more man-hours than one man has. Even if his goal was only a 4004, or even just a bunch of breadboards full of TO-92's.
Vacuum tube based might be possible for a very simple computer, if automating the glass-blowing and delicate assembly isn't too hard. After all, at least it's macro- rather than micro-!
Jeri Ellsworth has succeeded in making individual transistors on her own, but she didn't have to purify the materials herself. But it didn't take her a lifetime either.
In "Designing Analog Chips", Hans Camenzind tells the story of designing the 555 timer chip; he did the whole design, without a computer, up to cutting the masks out of Rubylith. It took him several months of nonstop work.
Based on these, I extrapolate that one person could do all the physical steps involved in bootstrapping to a computer from stone-age technology. (I won't say "one man", because that person might have to be Jeri.) And I think they could probably do it in substantially less than a lifetime.
But I don't think it would be possible for one person to do all the intellectual work, or it would have happened long before the advent of agriculture.
And I think it would be a lot more fun to do it with some friends.
I am not an expert on the subject, but I suspect making a facility that can manufacture thousands or millions of transistors, and then operating that facility would take obscenely more man-hours than one man has. Even if his goal was only a 4004, or even just a bunch of breadboards full of TO-92's.
Vacuum tube based might be possible for a very simple computer, if automating the glass-blowing and delicate assembly isn't too hard. After all, at least it's macro- rather than micro-!