sys config probably.
1st problem is your running vista… i’d take windows 98 over vista
2nd problem is its a PC… 
to get into BIOS, just turn the pc on and i believe its either press ESC or one of the “F” keys (I wanna say F10)… if you are unsure just start tapping the whole upper row on your keyboard… you’d be bound to get into it. Like mentioned look for a section dealing with Power Management… I think “Wake on Lan” would be what you’d be looking for, meaning it will turn on when there is an Internet connection available…
If you can’t find it… just dump a copy of Windows 7 on your PC, start fresh… problem solved… sounds like you have some malicious spyware or virus.
Entry to BIOS…keystroke varies from brand/BIOS version
I don’t believe it’s WOL because it’s a specific time every night. WOL would likely be sporadic.
Agreed that Vista sucks but it’s not the culprit here I’m sure, nor is it likely malware/virus. Not that it’s impossible but I’ve never dealt with a virus or malware that force boots a computer.
When did the computer begin to behave this way? Recently? If yes what changed? Any software installation, windows updates etc…
Troubleshooting is a basic procedure…time and alterations are crucial to diving in and actually figuring things out. Computers aren’t magical creatures and logic usually prevails.
Added—
Oh and if it’s a BIOS setting throwing Win 7 on there of course won’t solve the issue. 
This has been happening for a while now, at least 6 months, probably more. It used to do it sporadically, at first, so initially I thought whomever used it didn’t put it to sleep properly. So unfortunately for me, I don’t know the precise time it started happening. Then it started doing it every night and I just dealt with it for a while, then I really started to investigate the problem, which is how I got here.
Are BIOS screens different for all computers? I can’t understand why I cannot find Advanced settings on mine. It seems to basic, I don’t feel like I can control anything from it.
The BIOS screens are different per manufacturer, per version. There are literally thousands of screens you can see. You’ll have to look in each section and see if the “BIOS Power-On” option is turned on at any time. It might be worded differently, or you might not have that option at all.
formatting it will, that’s why i said start fresh 
Formatting doesn’t change BIOS settings so if it’s a BIOS setting and not a Windows issue formatting would do nothing to resolve the issue. 
Do not take your advice from this guy
Try updating the bios firmware
That was my next step, I was just a little worried if I screw it up, I know it can F up the entire computer. I understand computers, but don’t trust myself with them when it comes to important things.
I don’t think I’ve come across a bad BIOS upgrade yet. I’ve upgraded literally hundreds of them too. If it does go bad it can be lights out for the computer though; or extremely tough to fix. You should be fine though. Is it a name brand computer (HP, Dell, Sony, etc?), if so can you give the model, full model number/(service tag if it’s a dell)
I updated the BIOS last night and everything went well with that. Unfortunately, it didn’t change anything and the computer was running this morning when I came out to check on it. I looked a little further into my BIOS and it seems like the important features (Advanced menus) are just not available with this version. There were a few posts on the internet where people were trying to unlock that feature, but it looks like the risk of bricking the computer is high if it doesn’t go right.
Anyhow, my computer is a Compaq CQ60-214DX, running Vista home basic. I have InsydeH2O Rev. 3.5 and updated it to F65 (or64?) for my BIOS.
edit: seems like you fixed it…
Do you have any scheduled scans (ex: AVG scan) or system jobs running around your time… if so, the scheduled job might be maxing a failing CPU, RAM, etc…
I just can’t see how this started all of a sudden without a manual change through the BIOS.
Have you tried leaving the laptop plugged in a different outlet?
So you’re running BIOS version F.65? Keep in mind that you might not be looking for Advanced in the BIOS, you might be looking for Power options. Have you checked scheduled tasks? Are you doing a shutdown on your computer and then it powers on? If so it has to be either a scheduled BIOS Wake time or a Wake On LAN. If it’s wake on LAN then is there another computer on your home network that stays on? Maybe there is an option in the router to send WOL packets?
I never saw it used but have noticed that option in several routers. Not a bad suggestion to check.
Yes I’ve had it at different houses and it has still woke itself up.
Yes it is version F.65. I dont turn it off completely each night, i just close the lid and it sets the computer to hibernate. There are no other computers that stay on each night, just my wifes laptop, but that gets shut down to hibernate each night and doesn’t get woken up. I’ll check the router when I get home and see if there is something in its settings.
I searched through my BIOS screens and there are no options for power management, special features, etc. it is really really basic and almost seems useless. I listed what tabs are available a few posts back, id list them again but I’m at work now.
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I also checked scheduled tasks and there is nothing running anytime near 1am.
Try unplugging the router tonight and see if the computer still wakes up. If it does, you can rule out wake on lan stuff.
Then try shutting the computer down completely instead of hibernate. Does it still power up? If so, you can rule out scheduled tasks as well as anything software related.
:word: disable wireless and/or unplug the ethernet.
I reset the router today and went in to see if there was anything to wake it on LAN and there are no options to do so, however it does have the ability if one wanted to, they would have to manually do it with port switching or whatever. Definitely something I haven’t done and won’t be doing. I’ll unplug the router and modem tonight and see what happens in the morning and report back. Then I can try to turn it off completely and see what happens.
If I change the clock on windows to just before 1AM this evening and shut the computer to hibernate, will it work the same way and trick the system to think it is 1AM so I don’t have to do an experiment each night? Or do I have the change the clock in BIOS (that is one thing I can do in my BIOS version).
If you unplug all network capability, and set your clock ahead, I’m sure that will rule out plenty of things. Do it now… Takes less than 5 minutes to test this. You wont.