Do I need a openGL context ( HGLRC ) to call glDeleteLists or glDeleteTextures?
Yes
what if I removed the HGLRC before the call to glDeleteLists or glDeleteTextures? Will the textures than be alredy removed?
It would probably be faster to just try it, rather than waiting for someone to tell you the answer.
Almost certainly not. Once, I had a texture memory leak where I didn’t delete all my textures. Since I was testing the app, I was running it a lot. Eventually, I was unable to get an accelerated device context, and I had to reboot the machine to make it work.