Depending on what version of windows the laptop is running.
When you first power the laptop on, and as soon as the laptop starts to load windows, repeatedly tap the F8 key on the keyboard of the laptop.
If you catch the windows loading menu in time.
Either select the option of last good known configuration.
Or choose safe mode for windows.
Once windows has loaded if selecting the last good known configuration option.
The system should load windows without sticking at the welcome screen of windows there after.
The same also applies to if you choose windows safe mode once windows has loaded in that selected mode.
If none of the options fix the loading and hanging of the laptop at the welcome screen of windows.
Use the same F8 key on a clean power up of the laptop.
Choose safe mode again, once windows has loaded in safe mode.
Open up backup and restore of windows.
You should see a window open with a list of backup and restore point made.
Each restore point is where a bit of new software or a program, or even a windows update was performed.
Click the tab show me more restore points.
Choose a restore point from the time and date listed before windows started to encounter the problem of getting stuck at the windows welcome screen.
Let the system restore run, it will reset once done.
Hopefully fixing the problem.