Try the below mentioned steps, this will definitelyt helps you in solving your problem:-
Step 1: Restart the system in Safe Mode with Networking. Keep press F8 when the machine starts to boot up.
Step 2: Delete startup items of Win32/TrojanDownloader.Waski.A virus. Press Win+ R, type “msconfig” and click OK.
Step 3: Remove registry entries of Win32/TrojanDownloader.Waski.A virus. Press Win+R to open Run, type “regedit” and hit OK.
HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionWinlogon "Shell" = "[random].exe
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System “DisableTaskMgr” = 0
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System “DisableRegistryTools” = 0
Step 4: Show hidden files and delete related files of Win32/TrojanDownloader.Waski.A virus. Click Start menu, select Control Panel, and search Folder Option.
%AllUsersProfile%\random.exe
%AllUsersProfile%\Application Data\.dll