The main threat to my computer is the viruses that I can get with different office documents.
I think that's not true for a long time already. The main threats are completely different these days.
I mean main but not single. 
That's also what I meant - macroviruses are quite a marginal threat today, not one of the main ones (IMHO).
I ask those questions because I never saw Avast curing infected files - usually it suggests to rename or move them.
File infectors (i.e. viruses that modify files as their means of spreading) are quite rare today. Nearly all malware you see today are various backdoors/trojans/worms; there's no "curing" for their files - to get rid of them, their files are (more or less simply) deleted.
OpenOffice documents are basically renamed ZIP archives (Deflate) with data content (mostly XML files) packed in it. So basically you just have to unpack the Deflated container to see it's content...
Well, I admit I don't know anything about OpenOffice format... unpacking ZIP archives certainly isn't a problems (and avast! would do that, no matter if it's renamed or not). However, to remove macroviruses from them would probably mean understanding the particular XML format and modifying it somehow (but as I said, I don't know the format, so it's a pure speculation from me).
Right now, avast! certaily can remove files from those ZIP archives, but I'm not sure if it's the best way here.
