For some reason Windows.old folder was not there in the Cleanup service and when I tried to remove it manually it refused due to some kinda permission. I had to use the Windows 7 Setup disk and delete it from a command prompt in the repair section.
I was having that issue as well. It's odd that i don't have permission to delete certain files in that folder. You can fix this issue by downloading Unlocker 1.9.2 (Link:
http://filehippo.com/download_unlocker/download/93ffae8a5bad6c1fd1eed8ad1bfaae10/)
Note: it takes a long time to delete the files and for some reason in windows 10 the program makes windows unusable until it's done. I have never had any problems with this tool before. I haven't deleted it all yet for that reason. So be aware of that. But it will fix your issue.
Now, as for windows 10. So far i like the new look. There are a lot of new tweaks here and there that makes it look more modern. And i am happy to see that windows new settings menu have been vastly improved over Win8. But you still have the old control panel which i think is a design flaw. If you are gonna make a new settings menu, stick to it. Don't have a Frankenstein setup with 2 settings menus that can do the same thing.
The biggest flaw i have found so far (in my opinion) is that Win10 is still using that bullshit trustinstaller from Win8. You know, that thing that apparently are the owner of all your files and folder in C:\windows, C:\programs, and C:\programs x86..
I made a folder in c:\programs called "test". I then tried to delete it without adding anything to it. Windows then said that i have to provide administrative permissions in order to do it. If i made the folder myself, it shouldn't ask. besides, i have no password on the user. So why even bother asking? Anyone can just click continue. So what's the point?
I can fix it by granting myself ownership, but i still don't understand why it has to be this way. It worked fine in Win7.