The "snif" test is unreliable.
Remove ALL components, i.e. hard drives, floppy, cd, etc. and start from scratch, slowly. (Don't add any devices until you've gotten a successful boot (complete post) at the most basic point.)
Bad, wrong RAM modules do not usually cause a NO POST scenario. Incomplete post yes, no post no.
If you're not POSTing then what may or may not be on the HD is not an issue, you apparently aren't getting that far (to the HD).
Removing the battery for reset only takes a few seconds. That happens in just the amount of time that the batt. is out.
DO NOT add/remove any device while the psu POWER is on.
The PSU fan runs on 12vDC, at least one of the power leads off of the mb power headder is about 12vAC which is REQUIRED for some mb functions.