Basically, I screwed up. I d/l The latest version of Nero (Nero_Platinum_2019_Suite_v20.0.05900___Content_Pack_1-2). It worked fine, except one minor problem. For the life of my, I forgot what. Anyway, I uninstalled it (I thought). Like a fool, I wanted to make sure there was absolutely nothing... mentioning Nero was on my compute; so I got into my registry. I looked up everything that Nero was in it and deleted it. Like I said, I screwed up. I should have made a copy of the registry before I did anything to it. :-( Well, I did it, rebooted it and everything ran fine. I tried again to install Nero again. there was a major f***-up. Near the end of the installation, it wouldn't complete. "The installation source of this product is not available. Verify that the source exists and that you can access it." I tried to use earlier registry backups; but to no avail. Knowing that, am I SOL? I tried to use the latest version of Windows; but it too wouldn't happen. Which leads me to another problem. I have a USB drive which I loaded the newest Windows as I boot drive. I got into my BIOS and specified that drive as 1st. Guess what; it wouldn't let me. All things being the same, would you please help me. I'm out of options. Take care and God bless.
No system restore point? You said you tried registry backup.I'm assuming you went here: C:\Windows\System32\config\RegBack Windows keeps a reg backup in this location.Maybe try a windows refresh.
I already wen there. There wasn't anything that folder. It could be because I did install the latest edition of Windows 10 before I realized the problem with Nero. Now, you mean Windows refresh or Windows reset? If I reset it, I'll lose all of my settings and applications. I don't want to go there...
im giving my opinion u used nero during the XP days and even then i never like that burning software to big to heavy to much junk on it and consume tons of resources ....now to current problem if u can boot into windows back up all your stuff and do a clean install is the only way to truly get your OS running right again sense u dont have a clean back up image to restore to....their are a few registry repair programs out their but is not guaranty that it will fix your issue.
If nothing else works, boot from a linux usb flash drive and copy the files you want to keep to an external drive, reinstall windows, boot from the flash drive and copy your files back to your new windows installation. The reason I recommend a bootable linux flash drive is that linux doesn't care about windows permissions so it'll copy the files without issues (99.9% of the time) where if you use a PE boot flash, permissions can be a problem.
Normally if you uninstall a program that hook itself deep to the OS you have to restart OS to fully complete the uninstallation process before clean the registry. But from the read "The installation source of this product is not available. Verify that the source exists and that you can access it." sounds more like the installer itself is conflicting. The installer will be involved in area of temp folders in AppData\Temp and likely Windows\Temp. Possibly existing leftovers in WinSxS, System32, System32\drivers, Program Files, Program Files\Common Files, C:\ProgramData and check around all 3 folders in AppData for any Nero leftovers. Lastly clean the registry again, then close regedit and open again to scan all kinds of Nero references with ALT+F (and F3 find next), from top to bottom again to make sure no any kind of references left, restart OS and retry install. That's all i would attempt fix if that problem occur on me. Also check Environmental Variables in System Properties for User Variables settings, likely nothing unusual but just checking. I do hope you didn't overdeleted reg entries that deleted other important items which i did once due to regedit being lagging with too many list expanded and i overspammed deletion, caused OS fail to boot with zero repairability.
you just need to remember witch version eg: nero intaller you use in first install i presume nero trial whatever..., re-install exactly the same checksum and then use windows build in uninstall. the nero trial key will remain in you´re registry etc..