logon logoff loop

I am running (but not very well hence this post!) XP home edition SP2 + all current Ms security and other downloads. I run zone alarm, norton2005 , & spycatcher. also run sweeps with adaware and spybot. At some point this weekend something happened and now on switching on I get the MS welcome screen but hitting anyof the users reults in a brief attempt to logon and then it logs off again.

No spyware sweeps (other maybe than spycatcher which is 'real time') had been done since the previous closedown and succesful start up.

I can logon (to any user, including administrator) in safe mode.

I have seen some old posts about wsaupdater and have checked the registry but to my untrained eye it looks fine. Userinit is properly set and theer is no trace of wsaupdater.

Restore does not work for some reason.

Does anyone have any ideas ot try before I take a bifg hammer to it and try to go back to factory default?

Any and all help more than gratefully received!

 

If you can get into safe mode, put your XP disc in the drive, press start, then run, then type in sfc /scannow,(note the space after sfc) and Windows should replace any protected files, that have been corrupted.
Let us know.

 

Unfortunately Dell saved 50p and did not supply any backup XP disks.

 

Logon to any administrator account in safemode
start>run>typein
msconfig
In the start up tab untick all lines referring to your antivirus
restart normally.
If this works uninstall and reinstall your AV
If not go back to msconfig and tick disable all
restart normally
If this works
re enable each line in msconfig until you find the culprit.
Reinstall or repost in the malware forum if you can't identify it
If this doesn't work
On the general tab in msconfig choose diagnostic startup and try again this way can be a long process good luck

Studio T

 

I am surprised that Dell did not supply the backup, on their own restore disks.
Must have changed over the years.
Studiot has given you the best way to find the culprit, without a disc, and should give you back your system -as he says, time, and plod away- go all the way, though, just be patient.
(A friends xp disc might work,for sfc /scannowif it is sp2, and your system is sp2 - same basic disc -all dell do is streamline it to suit their backup )