What OS are you using?
What protection do you have?
How long have you been having this problem?
Have you tried opening Task Manager (Ctrl + Alt + Del) and going to File > New Task and running explorer.exe?
You're trying to use System Restore, correct? It's not guaranteed to work, but open Task Manager and go to File > New Task. When prompted, type in C:\WINDOWS\system32\restore\rstrui.exe and click OK.