Features like Folder option, task manager and regedit are mostly and commonly disabled by viruses. Unfortunately, anti-virus software doesn’t really care about these restrictions and do nothing to re-enable them.
Here is a free tool that can bring back your disabled folder options, task manager, regedit(windows registry editor), search, run , show hidden files and folders, etc options.
RegainPower is an open source program that could re-enable above mentioned problems. It is very small in size (743Kb) and USB portable, just run and select features and click OK. (Some features requires restarting the system)