but can the 32bit antivirus read the 64bit registry. unless it was designed to do so then the answer would be NO.
let me better explain. windows 64bit was designed to work with 32bit applications but in order to do so Microsoft had to build a special section in the 64bit registry for 32bit applications to function called the wow6432node (it is an exact mirror of a 32bit registry inside the 64bit registry) a true 32bit application cannot see anything outside of that area of the registry. so to make a long explanation short if you are running a 32bit antivirus it will load and appear to function 100% however there is a whole higher hierarchy to the registry that this application will not be able to see or provide security on.