Black screen with blinking cursor following schedule of avast boot scan

I read recent posts on this subject with great interest. I encountered an avast window that said a threat had been stopped and a boot scan was necessary to complete the repair. I elected not to initiate from that pop up. I closed other open programs/windows and scheduled the boot scan from the avast product itself. The boot scan never started as I have seen it in the past. I just got the black screen with the blinking cursor. I eventually powered down the laptop and then tried to reboot. I get a few seconds of Dell on the monitor before it reverts to the black screen. No luck with F8 to safe mode. I inserted the operating system disk in the CD drive and I get no response. I hear the drive move and seem to recognize the disck, but I don’t get any prompt. The blinking cursor prevails. I saw that a Master Boot Record repair was the happy ending on a thread that began on 3/28 amd ended on 4/4. I was hoping to get some guidance on what should be happening when I put the OS disk into the drive prior to powering up. How do I get the machine to recognize the disk and try to boot from it (or tell if that is actually failing)? Any advice would be greatly appreciated.

As already explained here by an Avast developer in another thread, the only thing that scheduling a boot time scan does is putting a key into registry… So, I am afraid what happened is just a coincidence and has nothing to do with Avast.

If you need to repair the MBR, you need to boot from the CD (i.e., change the boot order in BIOS), otherwise it still boots from the HDD (as you have noticed).

Please forgive my ignorance, but I’m really a novice. I’d hire somebody to help me with this, but I’ve been out of work for some time. Are you referring the the procedure utilizing a flash drive with a download secured on another computer? Thank you.

No, I am telling you to boot from the CD. Go to BIOS, change the order so that it boots from the CD first. If you do not know how to go to BIOS, read the manual that came with your computer. Esc, F2, F10, Del and others are common keys to get into BIOS, press as soon as you have powered on your computer. However, I would suggest to get a help from someone who has no problem following these instructions to prevent complete data loss.

Thank you. That is clear. I was able to make the change to the BIOS and promote the CD drive to he first position in the order. I will try to boot from the CD next.

Although you state that the Avast developer maintains this has nothing to do with Avast - the exact same thing has happened to me this very afternoon.

I too got the Avast window that said a threat had been stopped and a boot scan was necessary to complete the repair - I shut down all other applications and allowed it to process. The boot scan never started as far as I can tell, and I have got a black screen with the blinking cursor. When I try to reboot I get the brief Dell logo on my monitor before it reverts to the black screen and blinking cursor. I cannot start in safe mode (F8). This not a coincidence is definitely related to the Avast boot scan. Something is wrong and we need assistance!

Once again, writing a registry key does NOT wipe/mess up your MBR. The infection does.

  • do NOT work as admin
  • do NOT disable UAC
  • definitely do NOT do both at the same time

Other than those three items, which I did not suggest I was going to do or had done - do you have any additional suggestions?

Yeah sure, same as the guy above - get your install/recovery Windows CD, boot from it and let it repair.

P.S. You do not get MBR killed when working under limited account. Really.

I’m sorry I don’t know what you mean by the statement “You do not get MBR killed when working under limited account. Really.” What is MBR killed and why would I think that I was?

Master Boot Record. Google it. Your computer will not boot from the disk without it.

P.S. No point in continuing the debate about admin vs. limited. Lesson learnt for next time, hopefully? If not… well, not my problem.

I’m sorry, and not sure why you are being so antagonistic. I’m also not certain what lesson I should be taking away from all this other than your insistance that Avast has nothing to do with my (and the other poster’s problems). I did not make any statement (and neither did she from what I read) about being “MBR killed”. We were simply looking for assistance and presenting our problems.

One would think you’d be able to at least understand why it would seem so unlikely that two different individuals using Avast would have the same experience after allowing a boot scan; and present your assistance without becoming nasty about it.

Eh… can we get back on topic? You need any help fix the repair procedure? Vista/W7 should fix it automatically when you boot from the DVD and tell it to repair.

Wrt unlikely - you allowed a boot scan after you have been infected. Both of you. Avast did not even get a chance to run that boot scan because your computer did not boot. Now what is the logic behind blaming Avast instead of the malware just avades me.

Can you?

  1. Schedule a boot time scanning.
  2. (carefully) Open regedit.exe and find the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager and the key BootExecute and post here the value of it?

They cannot do any such thing because they have unbootable boxes (damaged MBR) and the scan did not even run since the machine would need to boot in the first place. Whatever:

autocheck autochk *
aswBoot.exe /A:"*" /L:"1029" /heur:80 /RA:ask /pup /archives /IA:0 /KBD:2 /dir:"C:\Program Files\AVAST Software\Avast"

At this time I’m trying to locate the disc. Of the three Window’s discs that came with the Dell none are labled recovery disc. There is a Reinstallation CD for Service Pack 2, for Service Pack 3 and one for Vista 32BIT SP1. The computer was running XP, not Vista. Should I be looking for a differently labeled disc or using one of these three to boot from?

No idea, probably not for the XP one and even then it requires manual fixing via Recovery Console. No point in writing the instructions here until you try whether at least one of the XP ones is bootable.