[SOLVED] HELP ME! my macintosh HD access problem

hi guys, im new here, i made a terrible mistake, i changed my macintosh HD permission, i changed Everyone's access type to no access, i cannot open any any app, actually i cannot do anything, i've restarted and hold option key, choosed recover hd and choosed disk utilities then repaired disk permissions after all i restart the Mac and see nothing happens it doesnt even start anymore, im so screwed up all my job is in the Mac, can you help me please, im lion user dont exactly remember the version may be 10.7.2 and i dont have lion cd/dvd everything is in macintosh HD.

it was urgent, and i see no answer so i reinstalling the lion, it will take 2 hours at least, i hope it will solve my problem because i searched every where even in this forum none of the solutions helped me.

Solved

guys i solved the problem after re-installation is corrupted, here is how i solved my problem:

1) Boot into single user mode, type mount -uw / and press return

2) type chmod 775 /Volumes/'Macintosh HD' and press return

3) type reboot and press return

to boot in single user mode, restart your mac and hold command(apple) key with s (command+s), your mac will start with terminal.

source: here