Constant Rebooting Help!

I really need some help here guys, I'm out of ideas. My computer is always restarting, usually upon boot and often when trying to shut down (restarts instead of shutting down) Here's what I've done about it up to now...

1) Replaced PSU with brand new Antech 400w Smartpower

2) Tried new memory

3) Tried new video card

4) Tried new HDD

5) Disconnected power cable from surge protector and plugged it directly into the wall (thinking maybe it was a bad surge protector)

None of these have fixed the problem. I am going to try and replace the IDE cable and if that doesn't correct the issue then I am going to assume it's my mobo (Asus) but they will charge me if it turns out there's nothing wrong with the mobo. Any help here is appreciated...

 

try updateing the bios to the most current verison.

 

Yes, BIOS update might be needed especially if the mobo is old and you are using a PCI add-in card to connect the SATA drive.
Also I would concentrate on these 3 (but yeah, it cold very well be a bad mobo too but Asus? hmm not likely):
1) Incompatible or bad RAM (make sure it is a supported type also generic RAM is bad news period!)
2) CPU overheating, inadequate or bad fan?
3) Incorrect BIOS settings and/or excessive overclocking

Let us know if there is any change, also provide more info, how old is the mobo and other components? When did the problem start (after installing a program, component, etc.)

 

couple of more things that came to my mind a little later:

4) have you check against virial infection?

5) Any of the Hardware not working or causing problems as well? Bad Video card or certain device drivers are known to cause random reboots as well but until you provide more info on your system specs and when the problem exactly started, all these are simple "possibilities"...

 

1) Virus inspection done, I know it isnt that.

2) Memory is fine, like I said I tried using brand new memory and the problem still remained.

3) My mobo is fairly new P4P800.

4) My cpu is just lightly overclocked 5% and besides I have tried setting it back to stock and problem remained.

I thought for sure that replacing the psu would fix it, I am thinking it might be my mobo. A few strange things though, it never seems to do it in safe mode also after the computers been running for about 20 minutes or so I can leave it on all day without one reboot. Although when I try to shut down it will usually reboot on me.

 

Brand new memory doesn't mean it is compatible or even good! What make/model and type is it? Is it fully supported by your mobo?

Also try resetting your BIOS to 'safe settings' and then boot in normal mode to see what happens, if problem remains then it is a service or device driver that could be causing the problem or again these factors causing the mobo to behave that way so it could still be a bad mobo but check for the top 2 things first.

Also you didn't comment on overheating? Are all the fan running including the CPU's?

 

If you changed your harddrive first while the broken hardware was still in there it could have carried the problem on to your second hd and created corrupt win files looks like the same problem but isnt.

try repairing the win files before boot and installing the latest service packs might not work but its free.