"I hope for both Dell's and Microsoft's case that the investment was made without strings attached," King said.
Microsoft has already upset some PC makers with its Surface device, which represents yet more competition in the tablet arena, and the investment to Dell could irritate other hardware makers, said Roger Kay, president of Endpoint Technologies Associates.
Looking forward, Dell has to balance the demands of Microsoft with other investors like Silver Lake, Kay said. But given the debt position, Microsoft will have a say in Dell's future.
"It's not going to thrill OEMs, but Microsoft has to look after its interests," Kay said. "There's a lot of motivation for Microsoft to be involved."