If the vista mod is really confirmed to work, the W7 mod will work as well. Basically it doesn't matter to mod it with a SLIC2.0 (Vista) or SLIC2.1 (W7). Other words: If the approach has worked to activate Vista the same approach will work to activate W7.
Yes it can. If it is like my 3610, it has phoenix bios. However, I think the 3620 has Intel 915 graphics like my 3610. There is no wddm driver, so no aero. Also, the xp based driver is not on the win7 dvd, but gets downloaded from windows update. I've found that my 3610 with the Intel 915 really struggles with windows 7 after playing video for awhile and will overheat and shut down. If I switch to basic/classic mode, then it won't overheat. It is ok in basic mode, but I would probably go with xp if I did it over again. I upgraded the ram to 2gb with no change.