Black Screen after Logging In

So I installed Windows 7 on my laptop about a month ago, and a few weeks later installed it on my desktop as well. However, after two weeks or so of using it on my desktop with no problems whatsoever, it has suddenly decided to stop working.

When I start windows, everything appears fine. The Welcome screen displays and I can enter my password. Windows gives me the nice loading icon aside the "Welcome..." text and waits for several moments.

Now, normally, it would fade to black and fade back into my desktop and I could continue on. However, the desktop no longer appears. After I finished playing Oblivion today, I did a reboot as I always do (just to clear out the memory). But when I went to log on, it faded to black and nothing else happened. No cursor, nothing.

I did find that I was able to get the Control-Alt-Delete menu, but "Switch User" and "Lock Computer" are the only options that work; they take me back to the welcome screen so I can shut down or try with futility to log in again.

I am able to boot into Safe Mode, so I went to the UAC panel with it and created a new administrator account; same problem there. It just faded to black as soon as I logged on as well.

Now, the only things I installed recently were a few Windows Updates yesterday (but had to reboot after that, and it was fine), and a DirectX version (9.*, I forget which exactly), as well as the DirectX SDK. I have not rebooted since those two installs.

Do you guys have any idea what would be causing this black screen? An hour of Google searching has given me nothing to go from.

Any help is greatly appreciated.

Hello and welcome.

In a system working well, a reboot is never necessary for any reason. I have machines going for months at a time with no issues whatsoever.

You can boot to safe mode + networking. Then in the start menu, type system information. Use ctrl+s on the screen that opens. Then rar or zip the saved file and attach to a post using the paperclip. We can look at it to see what may be causing this for you.

If you have AVG, uninstall it because it is causing headaches for so many users. Actually, in your case, it's best to completely uninstall any antivirus and firewall apps to test.

Interesting what you said about rebooting; I find often that my computer slows up when I switch between high-RAM-eating programs (like Oblivion -> FireFox + Photoshop, or similar). A reboot usually fixes that.

Regarding the Firewall, I use Comodo and have seldom had problems with it before; however I will disable/uninstall it if necessary.

I'll get the System Information as soon as possible, parents are nagging me to help with the chores, so I may be delayed for a while. Apologies for that...

Alright, attached is the file you requested. Will be back after I help out my parents...

Thanks for your help!

Having Fraps startup with Windows may be casuing an issue so you could stop that from happening.

You can use msconfig for the start menu search box. Then see the startup tab.

If that doesn't do it, then yeah...try uninstalling Comodo because everything else looks alright.

Have a look in the bios for a setting called Plug and Play OS. Set it to yes if it's in there.

I see you're running SLI. You can try removing one card and boot, as a test. If it goes well, then we know the exact cause.

Also, you have 3 separate instances of sidebar starting with Windows. You can use msconfig to disable 2 of them as only 1 is necessary.

I went through the BIOS and didn't find a Plug-and-Play option; I went through "Standard CMOS features" and "Advanced BIOS features" but didn't see anything to that effect. I know all the BIOS systems are different, but do you have any idea where I should be looking specifically?

Regarding the GPU: I'm running a SLI-Capable card, but I only have one... could that be causing a problem? If so, why would it just be starting now, and how would I disable that?

And lastly, I also don't see Sidebar under the "Services" or "Startup" tabs of the MSConfig application... any idea why it's hiding from me? Maybe because I'm looking using safe mode?

Actually, I hadn't realized that 3 instances like that are normal. I checked my own registry and that's exactly what I have too. So we can look elsewhere at problems because that's not it.

I had a thought. Do you have a 2nd monitor or tv attached? Remove them temporarily and boot to Windows with only one monitor.

Does the desktop come up?

Nope; I'm just on a single monitor. :\