To do such stuff, i recomend you to boot in "Safe mode", it won't load the virus, as well any of thje start-up virus, giving you the remote possibility of the virus not hide you the folder, and the files as well...
This might let you use the Ctrl+Alt+Del stuff, launching taskmgr, killing process, killing reg keys, and then the files... hoper that workz, and remember, do not let the processname fool you, the windows update is a service, then is on svchost.exe, winlogon is a system process, DO NOT KILL IT, mdm is a system process, and alg.exe interacts with NtOsKernel directly, so, DO NOT kill the processes i told ya...