Have you been using your computer and somehow you managed to lock your keyboard? How do you unlock it? You can try pressing the following keys on the keyboard all at the same time.
ctrl+alt+shift+del
You can also try turning off the “Num Lock” key, by pressing if it still works.
If that doesn’t fix the issue I [...]

Is your computer’s sound card not working? Try going into Windows device manager then right clicking and deleting the audio device. While still in device manager there is a refresh icon that will make Windows XP scan for hardware changes.
Windows will then see your audio device again and try to install drivers for it. You [...]

Trying to add a PCI-E card to your Lenovo Thinkcenter computer?
The Thinkcenter S51 part numbers 8098, 8171, 8172, and 8173 will beep with code 4 2 3 3 if you try to install any PCI-E card, besides a PCI-e x1 card. The system only supports PCI-e x1. Please read the official answer from Lenovo [...]