what do you mean by task manager is disabled? are you able to click on the "open task manager" in the statusbar or when you click on it, it doesn't open up? what do you mean by i cant install or uninstall? do you mean that it gives you an error when trying that or when you open up any .exe file, nothing happens?
If so, download process Hacker portable version, run it and see which program is responsible of lunching this "checkupdate.exe" file. also try to monitor TCP connections that are linked to this process by using TCP monitor.or try using GlassWire.Also, if you want a good "pirated" windows, check TeamOS-hkrg forum, they even have windows 10 pro "lite versions" that are cleaned of all Microsoft bloatware like cortana, store,People and other useless apps.