Googol is a sentient computer. She acts as the orchestrator of the activities of Raymond, and at times, takes control of him to perform a hit.
Her programming originally had her running the Electronic Detective Agency at a profit, but her programming got corrupted, causing her to include assassinations in the business acumen.
She finally is able to convince, or corrupt, Raymond, causing him to kill their mutual creator, Professor Thornton.
Googol most likely gets her name from Google, or rather, from the word for which google was an accidental misspelling: googol, a word coined by Milton Sirotta, the nephew of mathematician Edward Kasner, used for 10^100.