Do you invest in computer stocks? Get ready for a rocky ride.

That's the upshot of a new report out of Compal Electronics, Taiwan's second biggest maker of notebook PCs, and a supplier to Dell (Nasdaq: DELL) and Hewlett-Packard (NYSE: HPQ). Last week, Compal warned that anemic demand for PCs is forcing it to cut estimates for 2011 shipments.

Predicting this year will close with 42 million units shipped (rather than the 48 million previously expected), Compal shaved 12.5% off the near-term prospects for the world's PC makers. And the damage won't end there. In addition to PCs, Compal also makes LCD televisions, and is cutting its forecast for that product by nearly 19%. (If you're invested in an LCD panel maker like LG Display (NYSE: LPL), or a TV seller like Best Buy (NYSE: BBY), you'll want to take note of this early warning sign.)

Who's to blame?
The most obvious suspect in the case of the disappearing PC demand is Apple (Nasdaq: AAPL). Around the same time that Compal was scaring the khakis off PC companies, another major contract manufacturer, Foxconn, was elating Apple investors. As reported by DigiTimes, Foxconn plans to ship 20 million iPad 2s this quarter, more than double the 9.25 million units Apple reported shipping last quarter. And while there's probably not a direct correlation between iPad sales made and PC sales lost, only a fool (small f) could fail to see how the iPad's popularity might contribute to waning demand for beefier computing devices.

What's it mean to you?
So is that it? Should you just put all your money in Apple stock and give up the "real" PC industry for lost? Not necessarily. Turns out, there is a light at the end of the tunnel -- it's just farther away than you might want. According to Compal, longer-term trends suggest a rebound in PC demand shifting into 2012, where notebook shipments from the company could grow as much as 20% over 2011 levels, to 50.5 million units.

If you think you can wait that long, though, then now might be a good time to start "accumulating" (as the Wall Street analysts term it) cheap shares of Dell and maybe even Intel (Nasdaq: INTC) or AMD (NYSE: AMD) on pullbacks in price. Intel today looks mighty tasty at just nine times trailing earnings. Dell shares can be had for less than eight times earnings, while AMD carries a mere six times multiple. As bets on revived PC demand go, it doesn't get much cheaper than this.

Want to see how Compal's predictions play out?