Trojens in my virus chest

I cought two Trojens from my ISP mail,Avast placed them into the virus chest,I wonder,may I delete them from the chest safly?

clean quarantine or delete
http://antivirus.about.com/b/2007/03/11/clean-quarantine-or-delete.htm

how to use virus chest. http://www.avast.com/faq.php?article=AVKB21

there is no rush to delte from virus chest…
if this is something you dont need…delete it
if this is something you may need, wait a week, right click the file in chest and scan it…
if it is clean, you can restore it, if still infected delete

hya
im new to all this, but recent scan shows alot of viruses/trojans in my chest.
how do i know which ones i need and which ones are real viruses.

am not a computer techi.
these were not on my PC last week

any help much appreciated
thanks