wsus 3.0 on windows 2003 classifications query

hi im running a win 2003 domain via isa 2006

previous my machines had receive most updates via wsus, but due to issues i completed a clean install of wsus but now receiving the below issue!!!!!

currently all my machines are setup for (automatic approvals) - due to previous wsus issue i have changed automatic approval (name) but (computer group) is same!!

currently i have only selected (security updates & critical updates)!!!!

currently there are 3 machines that can be viewed via my wsus, but show as below:

- dc - win 2003 not yet reported
- file print server - win 2003 not yet reported
- win7 laptop - (showing as windows vista enterprise edn & not yet reported)

workaround solution for updates:

questions 1.  i logged on individually to all 3 machines and directly connected to windows update and download almost all updates.  i thought this would solve (not yet reported) issue but still same - have i done something wrong here ?

troubleshooting:

access regedit and delete (windowsupdate) etc & susclientid & susclientidvalidation & looked at c:\windows\windowsupdate.log

question2.  as ive tried various things to resolve, what i would like to know is when i should download the others in the (classifications list) ie:

- definition updates
- feature packs
- service packs
- tools
- update rollups
- updates

questions3.  what is the difference between (security & critical updates) to above updates ?

note: i was advised to just tick (all updates) and leave (drivers)!!!!!!!!!

note: it appears that some troubleshooting techniques or answers may be correct for win 2008 but not for win 2003

note: i am also running a (windows internal database) and not sql 2005 or 2008