If office came installed on the computer as new you should be able to re-install it via the recover/restore CD's, or find it manually on the CD's using windows explorer. If it's not on the CD's but the PC came preloaded with office suite, from the factory, see If there's an extra "hidden partition" on the hard drive; some MFG's use a hidden partition to store the OS and pre-loaded software. If it was preloaded, but not on the CD, the office install/setup exe may be located in the extra partition.