Actually, Microsoft is making a profit. But they're doing so by taking a page from the HP book; murdering everything good about the company and tactically doing away with products, services and staff with little-to-no regard for the strategic implications. They treat their customers, staff, partners and developers with overt contempt because the only thing that matters to Microsoft's brass right now is quarterly profits.
There is no strategy at play because the board has vetoed any such thing. the closest they can come is a massive gamble on "the cloud" and "mobile", but that's a sucker's game because you don't win at either of those by alienating your entire customer base and ecosystem. Both require trust, and "mobile" requires some semblance of "cool". Microsoft can't accomplish either while grasping at quarterly numbers with blatant desperation.
Compare to HP which has just come through that particular looking glass and is now desperately trying to invest in R&D, only to have a huge problem hiring decent talent; it seems nobody wants to work for HP anymore because their name is "mud" amongst the bright and shiny engineers of the world.
Yahoo! is viciously cutting the deadweight in a desperate attempt to stem the bleeding, but thye have no discernible long-term strategy at all.
Amazon, OTOH, makes losses for tax purposes. They are investing in massive, massive growth at the expense of profits because their play is "utter market dominance." The goal is to be the only name in the various games they play, so that when the others are beaten back they can turn the knobs, Oracle style, and extract as much revenue as they want.
Google is doing fine, thankyouverymuch, on the quarterly numbers and so is massively investing in R&D. They plan to become the world's first true megacorp, an American chabol with overtones of Weyland Yutani. They're patient and willing to put the money and research into it.
Apple have everything they want and seem to have found a balance between researching new products and markets and simply raking in the cash. They have created an aura of customer, partner and staff trust and that allows them to absolutely dominate the consumer market.
Dell have realised that Wall Street is interested only in slitting it's throat in the quest for quarterly gains and has gone private. The goal here is to reinvest massively in research and completely change the basis of the company. It's a long-term strategic play - and a huge gamble - but if I had spare dollars, I'd bet on Dell. They seem to know what needs to be done and are slowly, but surely setting about doing it.
IBM is in a bad place. Wall Street is baying for blood and IBM is having to sell itself off a piece at a time to keep them happy. Their R&D occupies a larger and larger % of revenue as they sell off their various tentacles but is demonstrating a fairly flat return. The only hope they have for survival is R&D, but they are unlikely to be allowed to keep it.
Lenovo looks at all the Americans and shrugs. They'll let the yanks bear the R&D costs, deal with Wall Street. They don't have the concerns the other do and so they have decided to do one thing, and do it well: sell as many widgets as possible as cheaply as possible. Since everyone else is abandoning the "selling commodity tangible widgets" game, Lenovo just sits on top of a pile of money grinning like a Chesire cat. The mass market belongs to them and they know it. Given this, they are investing in acquisitions and starting up proper R&D in order to plan for the future. Eventually, someone will make widgets cheaper than they can. They intend to be ready.
So none of these companies really directly compare to one another. They are all trapped with different problems and have different approaches and hurdles to overcome.