Final answer:
America Online (AOL) is the company that transformed its operations to become an industry leader in the 1990s, predominantly by changing its focus to becoming a leading internet access provider and expanding through strategic acquisitions.
Step-by-step explanation:
The second-tier computer company that utilized a drastic change in its operations function to become an industry leader in the late 1990s was America Online (AOL). By pivoting from being an online game provider to becoming a dominant provider of internet access and services, AOL dramatically changed its business operations. It expanded rapidly by providing an accessible Windows version of its free access software and distributing millions of free trial CDs, leading to its predominance in the U.S. internet service market.
Furthermore, AOL's acquisition spree, which included notable companies such as Netscape and MapQuest, and its eventual merger with Time Warner in 2000, signaled its expansive growth strategy fueled by the online access economy.