think Ubuntu live bootable cd is better option, just put the missing file in pen drive and then boot your computer with ubuntu live cd, this will take 5-10 min and load its own OS and show you the files of your system, with derives , now just insert the pen drive and copy past the missing file in your system folder
Get a new hard drive, but b sure to check if its an IDE interface or SATA. Some good onez ar Seagate, Western digital. Insert d new hard drive then turn on d system. Enter BIOS settings to configure the new hard drive. Load your desired OS and your system is back 2 normal!