Dell has been actively snapping up companies as it tries to diversify away from personal computers, a market where growth is decelerating as Apple's iPad and other mobile devices pull consumers away.
Dell executives have said they view software and services as a key growth area.
My goal is to make software a meaningful part of Dell's overall portfolio.
When the PC maker announced its acquisition of network security provider SonicWall in March, a senior Dell executive vowed that more such deals were in the pipeline.
"My goal is to make software a meaningful part of Dell's overall portfolio," John Swainson, president of Dell's software group, told reporters on a March 13 conference call. "That means this (SonicWall) is not the last thing you're going to see from us."
On-again, off-again talks between Dell and Quest had broken off last month, sources have said. Dell has yet to publicly acknowledge any interest in buying Quest.
Quest said its board of directors has determined the new proposal is superior to prior offers.
Last week, Quest agreed to sell itself to Insight for $25.75 per share, after the private investment firm and new partner Vector Capital raised their bid.
The Insight-Vector cash offer of $25.75 a share had topped a $25.50 bid made by a "strategic bidder" that Reuters later identified as Dell.
Insight has three days to match rival offers, or adjust its own bid.
Aliso Viejo, California-based Quest is led by Chief Executive Vinny Smith, who has served as either chairman or CEO for more than a decade.
Any deal with Quest is fraught with complications as roughly 34 percent of Quest is owned by Smith, who took over in February after Doug Garn stepped down, citing poor health.
