hey guys.thanks for clicking and helping me.
First of all, i have to admit english is not my mother tougue.So there may be some grammar mistakes in my descrpition  ,but i will try my
 best to avoid them .  here comes the problem.
I'm learning C, not cpp.
Today ,when i open some old files in my folder(which is absolutely right,without mistake),it can be executed first time. but when i tried the second time ,   the problem appears.   here is the words on build log   
f:/codeblocks/mingw/bin/../lib/gcc/mingw32/4.4.1/../../../../mingw32/bin/ld.exe: cannot open output file D:\Files\2-3-3-4.exe: Permission denied
collect2: ld returned 1 exit status
Process terminated with status 1 (0 minutes, 0 seconds)
1 errors, 0 warnings
and,not a single file alone. every file is just like this .even the simplest "hellowolrd.c" can only be executed once.
in addidion ,my os is window-7 64bit. and c::b went well before . 
i've googled the problem for settlement . but the methods seem quite alike. first,there isn't any process related  running. second ,it isn't read-only.
i've reinstalled c::b  but it doesn't work.   i saw some guy sayed it's a bug. is it ?
i need your help badly
thanks in advance.