Solved: Windows 7 – Black Screen Blinking Cursor
Update 21 October, 2012 – After a few years of experience with Windows 7 and seeing this problem many times, I wanted to add another update to the solution. The information below, and especially the update below could well be useful, however I have found another technique that I think more often solves this problem. Please refer to this updated Black Screen Blinking Cursor III entry.
Well, I’ve had my first Windows 7 problem. I did a clean install “upgrade” of a machine to Windows 7 Home Premium, tested the machine and turned it back over to the customer. He called me two days later when he experienced the infamous (Vista) KSOD. He described the symptom this way: the machine was working fine the night before, but when he turned it on in the morning, it came up with the BIOS screen then went straight to a black screen with a blinking cursor. Yikes, I thought, this is too close to Vista for my tastes.
The machine is a Toshiba Qosmio A45-411 laptop. I’m not actually positive that this is strictly a Windows 7 problem. It turns out that the issue has to do with the computer not finding the hard drive after it wakes up from hibernation. To fix the immediate problem, I removed the hard drive from the machine and turned it on. With no hard drive it the machine, it tries to boot from the network (for some reason it skips over the CD drive which is first on the list). After the unsuccessful network boot, I turned off the computer and re-inserted the hard drive. Hit the power switch and it will again try to boot from the network, then, after a moment, will successfully resume using the HDD.
This particular computer had some problems with SATA LPM (Linked Power Mode) which were supposed to be fixed with a BIOS update. I have a suspicion that this is where the problem lies but I don’t have the time right now to fully sort this. My workaround for the problem is to disable hibernation on this machine as the customer is OK with that. You can read about how to disable hibernation in Windows 7 here. If you use the GUI method Brink describes here, there is a setting for disk power that might be interesting to fool with if you have the time.
EDIT: I’ve added another simple solution for the blinking cursor problem that is not Windows 7 specific.
UPDATE: Because this is one of the most popular items on this blog and I’m giving a pretty machine-specific solution, let me also include a general solution that might help someone.
You’ll get this blinking cursor problem often when your computer can’t find the operating system for some reason. There are three general categories for where the problem is most likely to be occurring (this is not an exhaustive list but covers 75%-80% of the problems in my experience). They are:
- Windows configuration failure
- File system corruption
- Hard drive failure
What you are hoping for is that the problem is File system corruption because that is the easiest to fix. Your Windows 7 installation disc is your friend here because you can boot your computer with it and ask it to do a repair. You probably don’t have this disc, but not to worry, you can download it from here. You’ll have to have access to a working machine and figure out how to burn a CD/DVD.
After you boot with the disc, it will offer to try and do some repairs, you can let it do that, but I’ve never seen this work. The next menu allows you to open a command prompt. Go to the command prompt and run the command CHKDSK C: /R. This might run for hours, especially if you have problems. If the result comes back that the program found “Bad Sectors” or completely fails for some reason, you’ve got a hard drive problem. If it fixes some file issues and tells you so, cross your fingers and reboot, your troubles may be over. If it says it didn’t find any problems, then your probably either have and Windows configuration problem or you might have a hosed Master Boot Record. These are going to be tricky to fix and are out of scope for this update.