System reboot by logon screen appears

[Blue_Geek]

hello bros ,
i am using windows XP . iti s about two days that i cant logon my PC. it opens noramlly, processes POST normally , load windows noramlly but while the logon screen appears , it reboots . i didnt not install any program , driver or anything else for a while excep windows updates which is downloaded and installed automatically. and if you think the problem might be with display card or display driver, wrong guessing because display card is onborad and i did not even installed driver for it . it didnt have any problem before . it is just two days it is driving me crazy . any suggestion is appriciated , thanks

[F1]

Have you tried to boot into Safe Mode?

[Blue_Geek]

Have you tried to boot into Safe Mode?

sure it boots from SAfe mode ,nothing is wrong with Safe mode. all what happens is with normal mode. in Safe Mode ,it does not reboot on logon screen . but in normal mode it does. please help . i am sick of it

[TurcoLoco]

sure it boots from SAfe mode ,nothing is wrong with Safe mode. all what happens is with normal mode. in Safe Mode ,it does not reboot on logon screen . but in normal mode it does. please help . i am sick of it

The registry loads in whole along with the selected user profile, the only difference is in Safe Mode, none of the startup entries (at any location) is initiated, also majority of the services are not started, only the bare minimum, system critical services are started (see screenshot).

So from what you have mentioned, the problem should be with either a startup entry and/or service(s). Your best bet is to use a program such as Autoruns which shows both, so you could disable (clear the box) the entries that you suspect. I'd suggest you click on Options and check the "Hide Microsoft Entries" option to be on the safe side.