Can I safely delete these trojans in AVG vault?

Just wondering if it is at all possible to delete these files without causing problems with my computer and how to do it.

On a recent new install (not quite deleting of all files) I reinstalled agv and found these files still in the vault.

Trojan Horse Downloader. Stubby C
C:\Documents and settings\Mum\Local Settings\Temp\farmmext.exe
Backup copy
Infected


Trojan Horse Downloader. Stubby C
C:\WINDOWS\farmmext.exe
Backup copy
Infected


Trojan Horse Downloader. Agent. AS
C:\WINDOWS\system32\ozaacuvt.exe
Backup copy
Infected


any help would be much appreciated.