I need help in logging on to a used computer I bought on eBay. I turn it on and I cannot log on to windows as I do not know what the previous users password was. How do I set it up to long on.

Did you get the windows instlation disk with the computer?

You have to do a fresh install of windows.

I do not have the install disk

If the system is healthy and the only issue you have is that you don't know/forgot your logon password, you may be fine. You WILL need a Windows XP CD, so if you don't don't have one that matches the version on your computer, you will need to buy a copy or borrow one long enough to try this:

I Forgot My Administrator Password! (http://pubs.logicalexpressions.com/pub0009/LPMArticle.asp?ID=305)

Please explain why you need an installation disk. Include information about the Service Pack level you have upgraded to, the computer make and model and what problem(s) you are having that make you think you need installation media. Someone might be able to identify a way you can manage without one.

Many manufacturers include a mechanism for burning installation media if removable installation media isn't included with the computer when it was originally sold. Use of such provisions as soon as you are able to acquire the necessary recordable media is a good idea.

If your Operating System came with the computer (typical) contact your computer's manufacturer.

If you purchased a boxed "Full" or upgrade version and have the installation key check with Microsoft.

I do not have the install disk

As mentioned, to what? What are you trying to do?

I've merged your two threads. You need to post an answer to the thread not start a new one if you need follow-up.

I suggest to try pressing the F8 key during the boot of windows XP. It will show you a menu where you can choose to load the windows in Safe Mode. Normally, after the windows starts up, there will be 2 (or more) user profiles, and one of them is the administrator. Hopefully its password is left blank, and you can login as an administrator. After that, you can create another user from the users icon in the control panel.

I suggest you contact the seller from e-bay and have him/her give you the password so you can log on and change the password.
Also try logging on in safe mode and see if you can make changes there.
Also when you contact the seller ask them for a disk for your PC.
Also try this when the password window comes up type in "user: "guest"
And hit enter maybe you can get on that way
Other than that you might have to do a full install.