Just backup any configurations file that you have in your box and try to reinstall.
If not succesfull, put a new hard disk in your box and reinstall asterisk.
You can try to run fsck from the command prompt but backup your files before continuing.
Check this guide
Note that the GUI isn’t supported here. If it is Asterisk GUI, it isn’t supported at all. If it is FreePBX, peer support can be obtained from community.freepbx.org/.