Win XP Boot Probs

billybob01

I have been trying for hours to correct this problem and need help. I have a WinXP Pro machine that was hit by the ZLob Trojan that takes over your web browser even though i had Windows Defender running and ZoneAlarm and Sophos AntiVirus all running. Anyway i eventually got rid of the Trojan but found i could`nt boot the machine up or even get into Safe Mode or even the BIOS!!! So i made an emergency boot disk and can now boot up windows as it was before the problem occured. But now i have found that i need this disc everytime i need to start my pc and still cant boot into Bios or Safe Mode. Any Ideas???

sprkymrk

Check your boot.ini file. Optionally, copy the files from the floppy to the root of your c: drive. Obviously you will want to check first by comparing the files, but this was just a quick idea off the top of my head before I head out to church this morning. Good luck!

PS - How about system restore?

TheShadow

What do you mean by "can't boot into BIOS". If you mean getting into CMOS setup then that is a function of the BIOS it self. While most motherboards can be flashed by a virus since most people don't turn off the function, most virus simply wipe out the BIOS. Having one reprogram the BIOS would be very new and interesting.

Changing CMOS setup so that it never tries to boot from the hard disk would do what you describe but I should think one could get into CMOS setup to fix it. If a password has been installed then pulling the plug from the mains and removing the motherboard battery for a couple of minutes would solve that.

billybob01

Well what i am trying to say is that

1. i cannot use the Delete button to enter the Cmos setup.
2. i cannot use the CD Rom to boot with in order to install a fresh copy.
3. i cannot use the F8 key in order to enter Safe Mode.

I can only start Win XP by having the XP boot diskette in the floppy drive.

TheShadow

pull the power cable and pluck out the battery for a few minutes then. When you turn the system back on it should say CMOS configuration error and give you and option to load defaults or enter setup and solve your problem. Make your you look carefully at how the battery is removed or you can break the holder. They are normally spring loaded with two small plastic tabs, don't break the tabs.

sprkymrk

billybob01 wrote:

Well what i am trying to say is that

1. i cannot use the Delete button to enter the Cmos setup.
2. i cannot use the CD Rom to boot with in order to install a fresh copy.
3. i cannot use the F8 key in order to enter Safe Mode.

I can only start Win XP by having the XP boot diskette in the floppy drive.

If you are using a USB keyboard, try swapping with a PS2 keyboard. It may be the bios does not support a USB keyboard until Windows boots up. Once you plug in a PS2 keyboard, see if you can enter setup with the DEL key or F8 for boot options.

Danman32

Are you sure it is the DEL key to get to the BIOS setup? Some PCs are a pain to get into the BIOS setup, but that has nothing to do with booting to XP or not.

The boot process is as follows:
The BIOS executes, then hands off execution to the master boot code on the absolute zero sector of the designated boot HD. If no HD, then other drives may be used depending on the config of the BIOS. Usually a floppy is always booted, CD boot can be disabled.

From the HD master boot sector code, execution is handed off to the boot sector of the active partition. Usually the partition has to be primary, but I have seen later OS installs that configure the master boot sector code to be able to boot to the boot sector of extended partitions.

From the boot sector of the active partitions, the OS's startup file is used. In the case of NT class OS (NT, W2K, XP, W2K3), NTLdtr and NTDetect are executed. They look to BOOT.INI to find out what controller/disk/partition to find the Windows directory to finish the boot process.

Since you are able to boot from floppy, you bypassed the master boot sector, boot sector, NTLdr/NTDetect and boot.ini on the harddrive and went straight to the windows directory. The floppy had its own NTLdr/NTDetect and boot.ini.

So, the hard disk may not have an active partition, the partition may not have a valid boot sector, the system partition may have missing/damaged NTLdr/NTDetect/Boot.ini files. Once you boot using your floppy, you can check what partition is set to active using disk manager, and check the boot files using Windows Explorer or command prompt. Be sure you are able to view system/hidden files.

TheShadow

Actually Danman32 I think that sprkymrk has the best call at the moment until we know keyboard type. Just about any motherboard made in the last 18 months to two years can bypass booting from the hard disk in cmos setup by moving to any of four controllers. It was all done in preparation for SATA drives and controllers. The old drive 0 controller 0 is no longer a certainty. He won't know until he can get into setup and find out if he is even pointing to the right hard disk. The same wierdness affects CD-ROM's, if the drive is not spotted on the post information screen (the black screen) checking the cd for a boot record won't occur.

Danman32

I did say the HD specified by the BIOS "... on the absolute zero sector of the designated boot HD."

To bypass HD boot that is set as the first boot device in BIOS, you usually have to hit a particular key. BIOSes vary which keys are the BIOS hot keys.

But it is important to understand the boot process so you know what to look for and what to fix.

billybob01

Well thanks for all the help guys you have been really kind. I have fixed the fault and the winner is............The Shadow!!!!!! Cheers dude, i re-seated the battery and alls well.

TheShadow

Danman32 wrote:

I did say the HD specified by the BIOS "... on the absolute zero sector of the designated boot HD."

So you did Danman32 and in the very first sentence no less. Sorry that I missed it and focused on active partition . However it was my understanding that he received no error messages, no "NTLDR not found" no unformatted or corrupted disk, no missing partition. While your explaination of the boot process is excellent there seemed to be a lack of error messages in this situation which indicated no devices listed. Remember this was not a new installation and the system was functioning. That points to zeroed or corrupted CMOS which I guess was the solution.

TheShadow

Glad that you are back on line billybob01.

Danman32

Because there was no mention of any errors, there's no way to tell where in the boot process the problem existed. Typically if the bios is barking up the wrong tree (or disk), it will return 'no OS found' or something similar.

I guess we needed clarification as to what was observed when a 'normal' boot was attempted. Since we didn't receive clarification, I figured understanding the boot process would help Billybob troubleshoot his problem. Since the PC could boot from floppy, it is booting through the BIOS, but BillyBob had no means of entering the BIOS setup to verify the disk boot sequence, which turns out to be the location of the problem.