Vulcan Ventures first invested in ZDTV in November 1998, acquiring a one-third interest from Ziff-Davis. In November 1999, Vulcan purchased the remaining two-thirds in a transaction that was completed on January 21, 2000. The deal (which permitted Vulcan to temporarily continue using the "ZD" initials and "red diamond" logo) was worth approximately $204.8 million.

In July 2000, it was announced that ZDNet would be acquired by CNET, placing ZDTV in the awkward position of using the initials and logo of a company that soon would belong to its main TV programming rival. However, a new name was already being worked on. On August 21, 2000, ZDTV was renamed TechTV, and a new on-air strategy was announced along with a slew of new series.

Soon, TechTV made a huge commitment to live broadcasting when it launched a nine-hour experimental news program called TechLive in April 2001. The show, which catered to daytraders and business types, never caught on with TechTV's geeky audience. In November 2001, following a massive round of layoffs, TechLive was divided into three one-hour shows. In the spring of 2002, TechLive was cut further into just one thirty-minute daily news magazine show, with a focus less on tech news and more on how technology changed people's lives.

Beginning in 1999, TechTV experienced repeated layoffs. In 2002, Silicon Spin (which launched in May 1998) and AudioFile (launched in August 2000) were canceled, but 2003 saw the introduction of several new shows (such as Performance, Robot Wars, and Unscrewed with Martin Sargent). "Internet Tonight" was to be replaced by TechLive, but new shows created by repackaging old segments were run for several months after TechLive debuted.

In late 2001 and early 2002, many Comcast cable systems dropped TechTV from their channel lineups. At the time, some viewers speculated that this was done to eliminate a competitor to the Comcast-owned G4. When Comcast's G4 Media acquired TechTV and merged it with G4 in 2004, a second theory emerged, which suggested that Comcast's actual motive was to lower TechTV's value, and ultimately its asking price.

TechTV Canada (now G4techTV Canada) launched on September 7, 2001 as a joint venture of TechTV, Rogers Media, and Shaw Communications.

In 2004 TechTV was introduced to the New Foxtel Digital format in Australia. After the merger with G4, TechTV (then called G4techTV) left Australia lineups as its international feed ceased, the channel TechTV occupied was replaced by a new Australian Network, the Crime & Investigation Network. On Malaysia's ASTRO network, repeats of the international feed was run for some time after the international feed ceased before starting to import G4TV programming and retransmitting them locally. In addition to those countries, TechTV had existence in Russia, and Great Britain. In Japan, Sony's So-net channel aired several TechTV programs until the fall of 2005 (They aired reruns after May 2004).