I recently reinstalled drivers and some applications provided by the vendor on my Lenovo laptop. Upon completion and rebooting, I found that I had lost my Welcome screen on Windows XP. I was staring with anguish at a Windows NT login screen. Below are a a couple of forum threads which helped me in determining the reason behind it as well as some good solutions.
The reason was a file – tvt_gina.dll which was installed with Lenovo’s ThinVantage Access Connection software. The solutions ranged from playing with the registry in Windows using regedit to doing the same in Windows Safe mode.
As for me, I uninstalled ThinkVantage completely and I got back my Welcome screen!