"The AARD code was a segment of code in a beta release of Microsoft Windows 3.1 that would determine whether Windows was running on MS-DOS or PC DOS, rather than a competing workalike such as DR-DOS, and would result in a cryptic error message in the latter case." (source)
"Electronic greeting card firm Blue Mountain Arts has won another round in its battle with Microsoft Corp. Late Thursday, a Santa Clara County (Calif.) Superior Court issued a preliminary injunction stopping Microsoft from setting up filters in its Outlook Express mail program that treated greeting cards from Blue Mountain as junk mail. " (source)
"In 2002, Be Inc. sued Microsoft claiming that Hitachi had been dissuaded from selling PCs loaded with BeOS, and that Compaq had been pressured not to market an Internet appliance in partnership with Be. [...] The case was eventually settled out of court for $23.25 million with no admission of liability on Microsoft's part." (source)
Microsoft has a long history of "sabotaging other products". I'm not saying they're stopping OEMs from bundling Linux, but I wouldn't make tinfoil hat jokes about somebody who's suggesting they do.
Long History. If so I would have though you'd have something more substantial to put forward than a few tenuous items from over 10 years ago.
1. A beta release of Win 3.1 that an over exuberant developer provided certain code for that was NEVER activated in the actual release.
2. A Beta release of Outlook express Spam Filtering that was, again, never released.
3. Microsoft stopping Hitachi from providing a PC with the option to dual boot an alternate OS on a Windows OEM licensed PC, which is against the OEM licence provisions. They did not stop Hitachi from providing the same PCs stand-alone with the (already unfortunately dead) BeOS OS.
IMO, I think we sometimes wish things were different in the IT world than they are today and then look for the tall poppy to blame. Microsoft are surely not the corner cake shop, they are big business and protect their investment with "competitive" (look up the word) "big business" corporate behaviour.
I see your items and raise you a "Microsoft kept Apple from folding in the late 90's".