Welcome screen hang, log on hang, black screen crash, and more!

Hello, I have recently (within the last week or so) started experiencing several problems with Windows 7 professional (64bit build 7601), (dual boot with Ubuntu) on my Dell XPS L502X (Intel i5 2430M). This post - Unprompted registry update, system restore and clock change refers to the first problems I noticed.
After that settled down, Windows worked well for all of half a day, then upon restarting got stuck at the welcome screen. I had no option but to reset with the power button. I started it in safe mode and all was fine, checked my drivers are up to date, then I ran check disk which found a few errors and fixed them. After a fresh restart, all looked promising - Windows loaded quickly etc, but when I tried to open anything (start menu, Firefox, Avast!... all tried on seperate restarts) the computer gets stuck - the little 'working' circle turns but nothing else happens. I have left it for an hour like this with no progress. Ctrl-alt-del also doesn't work.
Sometimes, instead of loading up Windows after I enter my password I just get a black screen with cursor and nothing else, which remains indefinitely. Once, I was logged in successfully any everything seemed fine, then the black screen appeared and nothing else happened.
Back in safe mode, I did scans with Avast Internet Security, MSE, Malwarebytes, all returned clean, back to normal mode, same problem. SO returned to safe mode, tried a system restore, which didn't work. Same problems. Tried another restore to a point before, still no change. I cannot get normal mode to work at all - hangs or crashes every time (no BSoD, just the black screen).
I have read that these problems may be down to a Windows update, which could explain why restore didn't help (am I right in thinking system restore won't change Windows update downloads?). I am at a loss now. As Ubuntu works fine I am fairly sure it is not a hardware problem. I have looked at the event log but as I am not (yet!) very technically adept they don't mean much... and I can't work out how to attach them here?
Sorry this is so long, I know these problems are discussed elsewhere but my problem seems to change every time I start up... I would really appreciate any help here!

If it isnt hardware running verifier will find the mis-behaving driver.




Driver Verifer

Using Driver Verifier is an iffy proposition.
Most times it'll crash and it'll tell you what the driver is.
But sometimes it'll crash and won't tell you the driver.
Other times it'll crash before you can log in to Windows.
If you can't get to Safe Mode, then you'll have to resort to offline editing of the registry to disable Driver Verifier.

I'd suggest that you first backup your stuff and then make sure you've got access to another computer so you can contact us if problems arise.
Then make a System Restore point (so you can restore the system using the Vista/Win7 Startup Repair feature).

In Windows 7 you can make a Startup Repair disk by going to Start....All Programs...Maintenance...Create a System Repair Disc - with Windows Vista you'll have to use your installation disk or the "Repair your computer" option at the top of the Safe Mode menu .

Then, here's the procedure:
- Go to Start and type in "verifier" (without the quotes) and press Enter
- Select "Create custom settings (for code developers)" and click "Next"
- Select "Select individual settings from a full list" and click "Next"
- Select everything EXCEPT FOR "Low Resource Simulation" and click "Next"
NOTE: You can use Low Resource Simulation if you'd like.
From my limited experimentation it makes the BSOD's come faster.
- Select "Select driver names from a list" and click "Next"
Then select all drivers NOT provided by Microsoft and click "Next"
- Select "Finish" on the next page.

If you are using win 8 add these
- Concurrency Stress Test
- DDI compliance checking

Reboot the system and wait for it to crash to the Blue Screen.
Continue to use your system normally, and if you know what causes the crash, do that repeatedly.
The objective here is to get the system to crash because Driver Verifier is stressing the drivers out.
If it doesn't crash for you, then let it run for at least 36 hours of continuous operation (an estimate on my part).

Reboot into Windows (after the crash) and turn off Driver Verifier by going back in and selecting "Delete existing settings" on the first page, then locate and zip up the memory dump file and upload it with your next post.


If you can't get into Windows because it crashes too soon, try it in Safe Mode.
If you can't get into Safe Mode, try using System Restore from your installation DVD to set the system back to the previous restore point that you created.

Thanks to JGriff2 & Usasma.

Using Driver Verifier to identify issues with Windows drivers for advanced users

Driver Verifier

Using Driver Verifier (Windows Drivers)

So, the problem is solved, but I have no idea how or why... I put off taking the advice above (thanks anyway, even though I didn't get round to trying it!) due to having Ubuntu also on the computer, just been using that and waiting for a day when I had the time/inclination to wrestle with the thing. Tried to log on to windows now and then, situation remained dire. Anyway yesterday my brother told me the same thing happened on his laptop, so I was going to try the above technique on both, but when I logged on to my windows it worked fine (will try to see whats wrong with his tomorrow). Very odd, but I'm glad it's sorted. Grown to love Ubuntu now, but its so useful having two OS on one computer!