If you deleted any word from your file and pressed the "OK" button then the file has changed with the deleted part with this i can't help you but check into your folder maybe you have only UNLOADED and not deleted because you said you don't know very well about scripts. If the file exists try using the /load command for more write (/help /load) in mIRC.
Now in the second that you said to take over your PC from mIRC, I am not very sure and i haven't see it since now that but i know if you have not any FIREWALL installed into your computer then a HACKER could be insert into your system and take over your PC, Also if you have not installed any FIREWALL and you don't want to, just disable the DCC from the "mIRC options" click on the "DCC" section and dislable it!
