dos prompt, regedit, msconfig enawada...task manager awith disappear wenawada,nathnam administrater block karala kiyala enawada..may be a virus attack..simple...AUTORUNS MAY BE
Process Explorer(Portable) Software eka download kara ganna.Eka taskmanager wenuwata use karanna puluwan.Stop the virus process and if u can do a system restore.!! do you have folder options...You will get them back from your registry