This is a usual problem. We delete a file and a message like this appears: "The action can't be completed because the file is opened by another process!" We can do 2 simple thinks to delete them.
1) Open the command prompt: press start, type cmd, press enter.
on the command line type chdir "the path of the file" (path of the file i.e. C:\users\user\desktop)
then type del /f "the name of the file including format i.e (test.txt)"
/f=force deleting of read only files
if this fails go to method 2
2) open notepad
del /f "path of the file including file name"
left click file
select save as
choose all files
save in c:\
(start type regedit press enter)
go to Computer\HKEY_LOCAL_MACHINE\SOFTWARE|Microsoft\Windows\CurrentVersion\Run
right click, new, string value.
name it delete
right click on it ->modify->type "C:\delete.bat"
restart your pc
remember to delete the value after restart (see the post below Control Startup Applications)
By Vasilis Nicolaou