Any Windows users out there that can tell me how to get XP running again?

I only use Windoze ExPee because my used computer already had it loaded when i bought it, and i occasioannly use it to test whether my web pages look OK under brain-dead Internet Explorer.

Anyway, a few days ago, it began demading a password for 'Administrator' access, and i haven't a clue as to what that password might be.

Thanks.

Hahaha, this is a virus. Saw something on a friends pc of this nature. Did you use bit torrent and installed some apps with keygen?
The only option I see here is reformat. This will save a lot of headaches . If you are ok with tweaking the registry then perhaps we can use the ophcrack (think I spelt it wrong) and we can break the password. You would need to download the cd from the internet.
Another option I may suggest is use a bootable cd with some antivirus for duhs. Ultimate dvd comes to mind and see if the clamwin is able to take the virus out.
Booting with a ophcrack cd still is the best bet.
Hope this helps.

Try booting into the recovery console and running sfc /scannow.

Hard to believe this is a virus, since i NEVER go online or download stuff with XP running. Remember i said XP came already loaded on a used computer, and i have no other machine running anything Microsoft, so i have no install cd or recovery console.

I am downloading the ophcrack live cd as i type this, and will give it a try. If a reformat is required, then i reformat to ext3 and it's goodbye Windoze (no great loss).

There are ways to obtain one.

Do you have a floppy drive ?
If you google for it than you learn that there is freeware utility to change any user password with a valid account on a windows XP machine without knowing the old password.
It starts up from the floppy
A I am not a windows user so I do not know if it works or not .

Thanks all. Will try the ophcrack cd trick today or tommorrow. If that doesn't work, i may try the floppy solution. (Yes i have a floppy drive) Will try to post the results soon.

I don't have the details handy at the moment, but there is a Linux program that can easily change any Windows account password in any XP partition that can be mounted from Linux.

When I needed this, I booted a Linux liveCD (something I usually have handy) in the system whose Windows can't be used because of lost password, then did a few net searches (from the browser in the liveCD) to find the URL to download that program into /tmp. Then I mount the Windows partition and run that program to change the password.

Edit: I just did that net search again
At the bottom of this page
http://www.pogostick.net/~pnh/ntpasswd/
There is a link to
http://www.pogostick.net/~pnh/ntpass...rce-100627.zip

In that .zip file there is a static linked Linux executable that you can use to change Windows password.
Some instructions are somewhere in that .zip or in that web site.
Most of that site describes a full CD for using the same tools. For me that would be less convenient than using a liveCD I already have plus one easy to download program.

I would go with ophcrack. I have it downloaded with me always just in case SOMEONE ELSE needs it. I am so selfless creature.

The short answer is: ophcrack seemed to do the trick. Only, i haven't a clue as to what really happened. When i made my ophcrack live cd and then booted it, it found my Windoze partition and began automatically probing for passwords. Except for an 'Assistant' password, it failed to find any password hashes. But rather than report that it failed to find the Administrator password, ophcrack said that password was empty. So, i booted to XP, and just hit Enter at the password prompt. This had not worked before, but it did this time, and XP loaded with Admin privileges (if that even means much to XP). So, thinking ophcrack may have blanked out the password for me, i assigned myself a new password, then booted to the ophcrack cd again. It found my new password, and did not blank it out. Is there an explanation for this, or do i just chalk it all up to MS weirdness and incompetence?

Ophcrack will not blank passwords AFAIK. I went through the entire post again and still do not know what caused this. Does someone else has access to this pc? Automatic updates is something that comes to mind too but then it is plain stupid if updates are done this way.
For some reasons I am not happy with giving you a solution - I should have asked you to use linux instead . But then again I just demonstrated the power of linux and so I think you should be dying to have it on your pc .
Anyway I do not know why something like this happened. I would advise you about a couple of things here.
1) Get the winduhs installation disk.
2) Back up all the drivers that you have
3) Run an antivirus, antimalware and anything security related that you can find (boy, this is a _lot_ of work).
5) Back up your registry too.
This will help in solving many issues you may have in the future.

Thank you for all your attention. No, no one else has access to this machine. It is not even connected to the internet. Am currently in Niraragua, and use internet cafes to do online stuff, using this rather old desktop to do all my offline work.

I have Linux, have been a Linux user for 6-7 years now, only use Windoze because the used computer already had it when i bought it. I only really want it for checking my (offline) web pages under Internet Explorer. Right after buying this used computer, i eliminated alot of Windows programs and files, defragged the hard drive, then used a Mepis installation cd to shrink the FAT partition, and installed Mepis on another partition, formatted as ext3. Windows was a bit confused at first by the change in disk size, but after the first boot, it seemed to be OK, until this spontaneous event recently where it began demanding a password, then spontaneously (i guess) decided it didn't need one after all.

Here's a possible clue: Something somewhere caused the system date to be set to a couple weeks into the future. I think it was set to Dec. 1, 2010 sometime around mid-November. Maybe your first advice was correct, and i have a virus lurking around on the Windoze partition, something that came with the machine. (???)

If i end up having to reformat the FAT partition, i won't bother trying to re-install Windoze, but will just make that partition another ext3 or Reiser fs.

Run chkdsk. Weirdness in registry often is harbinger of filesystem failure.

Ummm... during installing linux did you set correctly? Check the date you have in BIOS too. That would give us a fair idea what caused the date to change. Linux sometimes will change the date (if you are not paying attention during installation). Antivirus or antimalware is something that would tell is for sure if there is a virus in the pc. I do not think I have come across a virus that changes dates but I have dealt with viruses changing the admin password.
Honestly, dealing with linux is easy but with M$ somehow is exausting. The possibilities for something like this to happen almost is endless .

chkdsk reports no errors, and the date/time are set correctly in BIOS.