once files are in the virus chest can i delete them ???
There is no rush to delete anything from the chest, a protected area where it can do no harm. Anything that you send to the chest you should leave there for a few weeks. If after that time you have suffered no adverse effects from moving these to the chest, scan them again (inside the chest) and if they are still detected as viruses, delete them.
does it make any difference if they ate trojans or virus’s and it won’t harm the windows/boot files etc?
Doesn’t matter what they are, really.
If they’re in the chest, they are completely harmless, as avast stores them and keeps them from running.
Keep them in there for as long as you want. Better than deleting them and finding out that they were false positives, or even worse, something that your system needed to run properly.
As has been said, they can do no harm in the chest and early deletion (without checking) could have an adverse impact and you are up the creek without a paddle and no options left having deleted the file.
Welcome to the forums.