BSOD out of the blue. The screen saver was running

I looked up and the BSOD was there. I ran whatever diagnostic tool that was on the computer. and got an error message "pcw.sys is corrupt error code = 0x45d. I got as far as a dos prompt (x: drive whatever that is). I found the file but I don't know what to do with it. The computer will not boot!

Thanks for the link. This will take me several days to get through unless I get lucky. First bit of bad luck was a fail on booting to "safe mode and networking". The error message changed though. Now it reports that "after several passes the problem is still unknown".
Now it's on to step 3. I reprinted it so I could ask a couple of questions. I'll be using my XP to create and burn the CD's, but I'm worried that there may be version issues. Will the CD's I burn on my XP work on the Win 7 platform? Also the "boot the disk" is a video link so I'm guessing that the download I'm burning is "Windows Defender Offline". Is it? I'll watch the video tonight, create the Windows Defender Offline CD and see how it goes. Thanks so much

"3. If Safe Mode is not working, download, burn to CD or write to flash stick, boot the disk and run a full scan with Windows Defender Offline. If it fails try one of these FREE Bootable AntiVirus Rescue CDs burned to CD using Windows Image Burner or ImgBurn. You can also move the HD to another PC to scan it with Malwarebytes."

PS. I found this on the Tutorial page in the question and answers: froggie asked: My problem is that the OS screen doesn't stay up long enough to F12 or F8. It takes me directly to Welcome then dies.
gregrocker answered: You do not want the OS if trying to access one-time BIOS Boot menu, Recovery or Advanced Boot options on F8. If OS starts it is too late. Start tapping the key vigorously when you see the first BIOS screen.
I had the same problem and I was glad I found this. I think it would be good to add it to the tutorial proper.

So, here's where I'm at. I have been following KoolKat77's lead using Troubleshooting Windows 7 Failure to Boot. I created a Windows Defender Offline CD and downloaded malwarebytes onto a thumb drive. I eventually ran WDO's full scan on the Win 7 computer and it found no viruses or malware. I can only boot to the system recovery options and open a command prompt, so I haven't run malwarebytes. My computer is a Toshiba. They placed an "Administrator" copy of the operating system on a D partition. So far I've been able to follow the tutorial links without a repair disk using those system files. So I eventually came to "Windows Resource Protection could not perform the requested operation". After realizing I may have run scannow on the system files in D, I reran it on C:\ windows.... That lead to this, "Root cause found: Boot critical file C:\windows\system32\drivers\pcw.sys is corrupt. I don't know how to proceed. I haven't found any tutorials that directly address my problem. I'm wondering if I can run malwarebytes from a dos prompt. Why am I being redirected to a new page all the time? I have my browser set to prevent that.

The drives may be lettered differently in Recovery mode. I would follow step 6 to make the Win7 disk to do the repairs since it may work better and you may need it to rescue files to do a Clean Reinstall - Factory OEM Windows 7 if repairs fail.

Confirm that the 100mb System Reserved (preferred) or C is Partition Marked Active
then run Startup Repair - Run 3 Separate Times no matter what it reports.

You can use free Partition Wizard bootable CD to mark Active and also take a camera snap of your drive map and all listings to post back using the paper clip in reply box, which will help us better to help you. There are steps in the tutorial for using Partition Wizard Rebuild MBR - Video Help which may work or make it more likely Startup Repair will work after confirming the Partition Marked Active .

Keep in mind that the Toshiba factory preinstalled Win7 is a grossly inferior install to begin with, so if you want to cut your losses you can use the Win7 disk provided to rescue your files in Step 10, then with our help do a perfect Clean Reinstall - Factory OEM Windows 7 which will result in the best possible install of Win7 one can have.

"Confirm that the 100mb System Reserved (preferred) or C is Partition Marked Active" This is confusing to me. Volume 2 is marked D and volume 1 is C. The disk part screen image shows volume 2 is the System Reserved and marked active. I understand the procedure well enough to change it. Which volume do you want me to make active? Additionally, after your glowing endorsement for the Toshiba Window's installation, it's clear that regardless of the outcome of the next few steps a fresh installation is an excellent idea. The warnings say I could loose all my files (music, pictures, documents, etc.) with some of these steps. So, before I move forward I want to get those files off the computer. I bought a stack of CD's and a 32 Gig thumb drive, but my copy commands are rusty. A few years back an old friend sent me a CD that didn't work. In investigating why I found out you need to take steps to make the CD portable. Can you direct me to tutorials or brush me up on the syntax? I tried Wikipedia but they were too clinical (no examples). Thanks

I wrote that System Reserved is preferred, if you have it. This is even more clearly specified in Troubleshooting Windows 7 Failure to Start. So since you have determined that System Reserved is Active run Startup Repair - Run 3 Separate Times.

Everything else that possibly can be done to start Win7 is compiiled in the tutorial, so working through its steps instead of being sidetracked to other sources might be more productive. The steps lead up to if necessary rescuiing your files to do the superior Clean Reinstall - Factory OEM Windows 7.

You also ask about using Commands to copy out your data. There are two rescue disk options to achieve this offered in the tutorial, including the Win7 disk also being used for Startup Repairs and other repair attempts specified. But it will be necessary to copy these files to another HD or a USB drive, since the disk is needed to run the copy operation.