DavidR
2
We are are going to need a lot more information in order to try and help you.
Like, what is your Operating System, what version of avast are you using?
Where you online when trying to repair?
Why was it necessary for you to need to repair or delete?
I would suggest you visit the Off-Topic Forum and look at the Users FAQ thread, this could help and it lets you know the sort of information we need to help.
http://forum.avast.com/index.php?board=9;action=display;threadid=4818
HTH David