Quick Scan?

[badass]

I have a couple of questions I hope someone will answer.

1.  When do I use the quick scan? always do it first?
I have had the best luck when I use the bootscan, so most of the time don't even do a quick scan or a regular full scan.

2.  I have a second OS on my pc that was abandoned because my pc mechanic could not fix it.  I would like to recover it if possible so I was wondering: 
a.  Can I just go to it and right click and then do a scan on that only? 
b.  Can I do it in the state that it is in (Not being in use). 
c.  Should I do it in SAFE mode? 

I want to believe that if an avast scan is run, it would repair it as it was certainly a virus issue.  Do you guys think this is worth the risk? 

Or any other suggestions of course.

[Para-Noid]

I can't help you with question #2 but as to #1 I do a quick scan once a week (scheduled) and a full scan once a month (if I remember to run it).
avast has plenty of built-in protection reducing the need for really deep scans. 

[badass]

Thanks!