Open C:\windows\system32\dllcache and delete all the files in it (it is full of hidden files).

Download the latest version of 360 Security Guard Function Encyclopedia, which has a removable C disk, where other software can be moved to another disk to uninstall unwanted software! There is also a system disk in it. Just clean up the registry and put it on disk. And don't install software on the system disk at ordinary times!