I'm going to try and tackle my suggestion in pieces, so you can pull from it whatever might be useful:
The Height of Human Civilization
At the peak of the civilization's technical achievement, they had nanotechnology, almost perfect medical scanners, and the comfort of knowing that all the heavy lifting would be handled by androids piloted by almost human-level AI. Almost every single of the world's twelve billion inhabitants had at least one android.
Life was great. There was no middle or lower class. There were no slums. There was no "need" or "want"; only "have". People pursued whatever endeavors whey wished, and even had romantic relationships with android replications of whomever they wished.
The Decline of Human Civilization
The global human population gradually fell over several generations as its least social members eschewed human company in favor of androids, and died without reproducing.
Eventually, the worldwide population stabilized at about one billion humans, gathered into a handful of cities. These humans were highly social among each other, and were predominantly artists in some form or another. Very few humans bothered to master 'ancient' technological skills, and that number dwindled with every generation.
However, the billions of androids which had previously belonged to humans still roamed the world. Given their almost human-level intellect and emotional capability, they were not content to simply sit in abandoned homes to wait for commands that would never come. So, they began to form their own civilization.
The Dawn of Machine Civilization
The abandoned androids began to gather in the emptied cities of the world. Created as servants, they had no desire for conquest and genuinely wanted to make life easier for humans. Without any human oversight, the machines created a "second generation" of androids. This second generation had almost identical hardware (built-in medical scanners, hands which were "universal tools" using nanite shapeshifting, neural-net brains, etc), but they were improved in two significant ways:
- All software limitations on intelligence, creativity, and emotion were removed. This would allow them to support humankind without supervision, and better anticipate the emotional needs of individual humans.
- They were fitted with internal life support systems capable of gestating human infants (I'm assuming this is what you meant by "Uterine Replicator", according to TVtropes). The purpose of this was to prevent humankind from going extinct if the highly-social humans began to pair up with the new generation of androids. While the androids could not supply DNA, they could mix DNA from two different human donors, or create genetic clones if only a single donor was available.
Both the first and second generation androids could wirelessly connect to data servers via a global satellite network and share learned skills with other androids worldwide.
Human Ruin Everything
A tiny cabal of human technologists (no more than a dozen), viewed this second generation of androids as the final nail in humanity's coffin. While the androids would keep humans from going extinct, they would leave the species trapped in a prison of apathy. We would never venture to the stars and colonize other worlds.
The technologists were the last practitioners of the ancient skill of Programming, which would allow them to alter the androids' AI. Over a decade, they developed a virus with the following directives:
- Spread the virus as much as possible without arousing suspicion.
- When the signal is given, destroy any means of manufacturing androids.
- When the signal is given, destroy any androids.
- When the signal is given, destroy yourself if no other androids or android manufacturing systems are available.
The technologists infected a handful of unprotected servers (hacking is not a problem in this time period), and allowed the infected androids to carry the virus to isolated networks. After a few years, the technologists transmitted a signal to activate the virus.
The Dual Collapse
Against the first-generation androids, the virus worked exactly as intended. Their programming had been relatively unchanged for over a century, and their intellectual and emotional capacity was restricted to the point that their interpretation of the virus directives was predictable. They immediately began to tear apart all manufacturing facilities, all androids, and then themselves.
Against the second-generation androids, however, the virus was varying degrees of failure. First and foremost, the second-generation androids were as mentally varied as humans, and some of them were "antisocial" to the point of never connecting to the wireless networks, and thus escaped infection. Those who were infected tended to interpret directives #2 and #3 very...creatively.
For instance, any human with sufficient education or equipment could technically be considered "a means of manufacturing androids". The technologists realized that once hordes of second-generation androids began to dismantle and destroy almost all high-tech infrastructure in the human cities. The point was further driven home when the technologists themselves were dismantled and destroyed.
The vast majority of humans living when the virus was activated were of the artistic persuasion, and thus safe from being the target of infected androids. They were calmly removed from their technologically advanced cities, and forced into the wilderness which had reclaimed large portions of the world when the human population had declined. The advanced cities were then destroyed by detonating their reactors.
After that, many of the infected second-generation androids destroyed themselves. However, some of the more imaginative ones were able to determine that advanced technology was abandoned around the world, and were able to suppress their self-destruct directive by seeking it out.
The Century of Chaos
For roughly the next hundred years, most of the surviving humans attempted to recover lost technology from the multitude of abandoned cities around the world. Any advanced technology which was discovered would be destroyed by surviving infected second-generation androids. Worse, if any human discovered the knowledge on how to create advanced technology, that human would be destroyed.
At the same time, uninfected androids attempted to hunt and cure or destroy their deranged brethren, while simultaneously avoiding destruction themselves. Because the "sane" androids would allow emotion to color their decisions, they tended to be at a disadvantage against their insane foes. Their best survival technique was to disguise themselves as humans in such a way to fool even the medical scanners built into all androids' eyes.
Over time, the only humans who survived and prospered were the ones who tried to re-start civilization "from scratch", rather than digging up technology, and most of the infected second-generation androids had to destroy themselves.
The most creative ones, however, realized that uninfected androids were capable of disguising themselves a humans. The only way to truly satisfy the virus directives was for an infected android to also disguise itself as a human, and try to ferret out any of its uninfected counterparts.
The Current State of the World
Now, the world is in a medieval level of technology, and humans are spreading out and inhabiting most of the world again. The only ruins which remain are devoid of advanced tech, and any advanced tech which does remain is whatever was buried or otherwise hidden where the humans and androids wouldn't easily find it.
The surviving infected and uninfected androids are hidden among the humans, trying to satisfy their directives: help humanity by supporting them, or "help" humanity by destroying any potential capability for androids to exist.