Hello, there. My boyfriend was trying to reformat his dad's computer, and he did just that. But, when he restarted the computer and turned it back on, the icons didn't appear nor did the taskbar, then it would abruptly log him off from windows and bring him directly to the start up menu log in screen. Before I was going to start helping him fix it over the phone, I asked what kind of installation XP disk he was using. He said the same one that he used on his own computer. I told him that I thought you could only use one XP disc/product key, per computer. I'm wondering if this is the problem or if it may be something else. I'm also wondering if there is a way to get back his old operating system or to fix whatever he did. Any help will be greatly appreciated.

There are two potential problems:

If the install CD is OEM (vendor specific such as DELL or HP) the supplied drivers and enhancements will often create major issues and incompatibilities. If the dad's PC is proprietary, it may be possible to order a replacement CD from them for your specific model.

If the install CD is a Microsoft CD, the operating system needs to be the same version (say XP Pro) and you may be able to use it for the dad's PC if you have the specific 'CD KEY' for that PC (often bar coded on the BOX):
http://forums.thatcomputerguy.us/ind...48&#entry96348

The link that you sent me brings me to the page, but when I click on the link it doesn't work.

Link works for me - here is the complete text:

There are a lot of people out there who haven't upgraded to service pack 2 because they installed XP with a pirated CD key. This puts your system at risk since SP2 contains many security updates. But you may be wondering if you'll have to reinstall XP if you do come clean and purchase a license. The good news is that you don't have to reinstall - You can edit the registry to change your product key, or you can forego that hassle and use a handy little utility to change the CD key recorded in Windows to the new, legit key on your license (which will then be recognized as legal by the Windows Genuine Advantage program).

Download it here:
http://www.wxpnews.com/rd/rd.cfm?id=050913TI-CD_Key