After booting my Dell Optiplex GX620, I got the blue screen of death (BOD) with the 0X7B Stop Error: “STOP: 0X0000007B (0XF7A71524, 0XC0000034, 0X00000000, 0X00000000)”. It would not boot into a Safe Mode either. In the Safe Mode the first parameter of the error massage would change into 0XF7ABF524 with the rest staying the same.
I had a slight suspicion that all that was caused by a Trojan virus and not by hard drive failure as many post on the net would advise.
To solve this type of issues when you can not boot your PC, the bootable CD is absolutely essential item to have. There are several web pages dedicated to bootable CDs. In the past I have used “Barts PE” (www.nu2.nu/pebuilder/), this time I tried “Ultimate Boot CD for Windows” www.UBCD4WIN.com. If you don’t have bootable CD, try “List of live CDs” on Wikipedia or you can just search internet to understand how to make one. It may take some time but, it’s worth the time as you may need it again in the future. (you may want to remove the firefox or iexplorer from UBCD4WIN to make the ISO file smaller that would fit a regular CD)
Just to make sure HD was ok, I ran Dell utilities to check my PC components including the HD. It’s a bootable disk and would boot and run some tests. The utility reported some “bad blocks” as “Uncorrectable data error or media write protected”. Since I had more confidence in my hard drive than in Mcaffe virus protection, I downloaded another test utility from my hard drive’s manufacturer’s site (Western Digital) and ran it. WD’s utility fixed the bad blocks but, the BOD STOP Error message was still there.
After spending almost two days reading tons of posts and trying different things, I was more convinced that I had a Master Boot Sector (MBR) virus on my HD. However, no virus checker on UBCD4WIN CD had detected any virus. I couldn’t run Avira virus check du to license expiration issue. After solving the license issue using this post http://ubcd4win.com/...showtopic=14855
(you can also download the key directly from Avira: http://dlce.antivir....ndows/hbedv.key
) , I rebuild the UBCD4WIN and once I ran it ,Avira reported BOO/TDss.A boot sector virus (Kaspersky: Rootkit.Win32.TDSS.mbr, Sophos: Troj/TdlMbr-B, MS: DOS/Alureon.A, DrWeb: BackDoor.Tdss.4005). Avira could not fix it but, at least I knew what and where was causing the 0X7B Stop error.
HOW to fix it.
1. Boot the PC from UBCD4WIN and run MBRwizard (Start/Programs/DiskTools/Partition/MBRWizard).
2. Use option 1 just to look at your MBR info. Next use option 8 and save MBR on your hard drive.
3. Run Avira against saved MBR file. It should detect virus in the saved mbr file.
4. Use option 7 to wipe MBR or first 63 sectors. When asked to wipe MBR or first 63 sectors, choose “2” for just first 63 sectors.
Exit and reboot PC into Safe Mode (hopefully it will work this time) and run different virus checks to get rid of some other viruses and trojan you may have.