Some (many) years ago, their Prism converter was good. Now they use their website to hack your computer - or so it seems. I simply updated what I had installed from them (Prism) and then decided to browse through the options...And there was the "TOOLBOX" with very short descriptions of what it supposed to offer.
I clicked few links - nothing told me that I am installing applications. A bit later, while I was searching the web, a window comes up asking if I want to change my default searcg engine. I answered "NO" - and shortly after that I see a whole bunch of photoediting, sound-conversion, slide who and hell know what else installed on my computer.
To top it off – the home page of both browsers I use changed to NCH, the Google Toolbar was replaced with something from NCH – of course, without anyone asking my permission. And that is with antivirus running.
When I tried to uninstall the unwanted software using Windows Control Panel, the programs refused to uninstall, informing that I should finish the previuos "installation". (probably, another malicious code did not finish running by the time I switched off the internet connection just in case).
I removed the NCH add-on in Firefox, changed the home page back to what it was – but when I restart Firefox, everything is back – which means the NCH gadgets and their home page. I had better luck with Explorer – there it cleaned up the NCH from the first try.
Now back to uninstalling. I found the NCH folder and in the subfolders there (some 5 or 7 of them) were separate uninstallers for each one of their wonderful programs. Just one of them worked – the rest asked you for a feedback, tell you that all is uninstalled – and nothing changed. So I cleaned the registry with regedit
– searching for "NCH Software" and other names in their folders and deleting each one of them. Still did not fix the Firefox.
Now I have to run a deep virus scan and perhaps, restore the system to some previous points.
NCH Software is taking steps in the right direction for its users (Updated Jan 2016):
Is NCH Software Safe to Use?
Posting this here for those searching about NCH being safe, since the answers on this question are several years out of date. NCH definitely seems to have a shady past, but they've been working on honestly improving their reputation. Their installers still recommend (and can install) other NCH products, but from what I've seen there is no more third-party bloatware, browser takeovers, or any other behavior typically associated with malware. They're in the business of selling software, and seem to have realized that screwing people in the free trials isn't good for business! – Doktor J – 2019-01-10T16:24:36.647