Viruses, malware and spyware can sometimes render a Windows operating system (OS) unusable. If the Windows OS on your IBM ThinkPad T42 has been corrupted or infected by hard-to-remove viruses, your only option may be to restore the laptop's software to factory defaults and start over. Fortunately, this is easy to do on a ThinkPad T42 laptop.
Burn or back up important files before starting the recovery of your IBM ThinkPad T42 to a CD or DVD. Back up data files only and not the programs on your computer.
Shut down the laptop. Connect the AC power adaptor to the T42 notebook.
Restart the computer and press the "Access IBM" button above the top row of keys on your keyboard when you first see the IBM logo screen. The correct button on your keyboard depends on the model ThinkPad you own.
Press the down-arrow key to move the cursor to the "ThinkPad Product Recovery Program" option and press the "Enter" key. Once the "ThinkPad Recovery Menu" appears, press the "F11" key to start the recovery and restore process.
Follow the on-screen prompts to restore the ThinkPad T42's hardware settings and software to factory defaults. When prompted to do so, press any key on the keyboard to restart the laptop. Allow the recovery process to finish and wait for the computer to boot into Windows.