I initially had Windows 8.1 installed on my desktop but when I took my PC to fix a hardware issue, the computer shop service guy upgraded my os to Windows 10 (with my agreement of course). He used an ssd drive on which Windows 10 has been installed so that I wont lose my old work data (that was stored on C drive or on desktop). So it seems I have both 8.1 and 10 installed. Now the problem is some of the software that I had installed on the old os are still there. Obviously Windows 10 is not using those (i.e I am able to use the software but those are not being recognized as installed). I tried to uninstall some of the software and instead download a fresh copy for Windows 10 but when I double click on the uninstall option, in the end it says software uninstalled but the files remain in the folder. Can I simply delete those files and if I install a fresh version in the same drive will I be able to use it?