The economic downturn has taken a big bite out of personal computer demand, according to two recent ChangeWave surveys on PC buying among consumers and corporations. The results clearly show deteriorating computer spending going forward.

Next 90 Days: PC's Head South

Consumer Spending Trends: Only 8% of the 4,427 consumers surveyed by ChangeWave in late February say they'll be buying a laptop in the next 90 days - down 3-percentage points since November 2007. Most importantly, that's a record low for consumer purchasing in the past 12 months.

The same trend was found for desktop computer purchases, with just 6% saying they'll be buying a one - also a low for the year.

Business Spending Trends. In a double whammy, corporate PC buying has also slowed precipitously. In February, only 73% of 2,204 corporate respondents said their company plans on buying laptops in the next quarter - down 4-pts from a year ago. It's the same pattern for desktops, with corporate purchases down 5-pts.

But what impact, if any, is the PC slowdown having on major manufacturers? Let's look at three of the heavyweights:

Apple Mac Sales Remain Relatively Strong

Planned purchases of Apple (AAPL) computers remain relatively strong even in the slower PC buying environment.

Looking at the next 90 days, Apple remains the leader among consumers who plan to buy a laptop (31%) - down just 2-pts from the all-time high recorded in our previous survey. Apple planned desktop purchases (28%; down 1-pt) are also near record levels.

Importantly, Apple's planned buying numbers are up more than 50% from a year ago.

In the corporate market, planned Mac purchases for next quarter are also at near record highs, with laptops (7%) unchanged from previously and desktops (6%) down just 1-pt.

Most positively for Apple, the company continues to set the standard for customer satisfaction among PC users. More than half (53%) of corporate respondents using the Leopard operating system report they are Very Satisfied.

This compares to a 40% Very Satisfied rating for Windows XP Pro users, and a miniscule 8% Very Satisfied rating for Microsoft Vista Business (8%).

Another Ebb for Dell

In contrast to Apple, we find a far different story with Dell (DELL).

After experiencing a tiny uptick in planned consumer purchases of Dell PCs in our previous survey, they are once again losing traction going forward. Planned purchases of Dell laptops (28%; down 2-pts) and especially desktops (32%; down 4-pts) are considerably weaker than in our previous survey.

Dell is also plagued by a downturn in planned corporate PC buying for next quarter, with desktop (32%; down 3-pts) and laptop (32%; down 1-pt) purchases falling to new lows.

"It's like déjà vu, all over again," Yogi Berra famously said, and that's what it looks like as Dell once again resumes its market share slide.

Weakening Hewlett-Packard Computer Sales

Another major player, Hewlett-Packard (HPQ), also exhibits weaker PC sales going forward - led by a big drop in consumer planned buying of desktops (18%; down 5-pts) and laptops (19%; down 2-pts).

In terms of corporate planned purchases, H-P also looks weaker going forward, both for desktops (17%; down 1-pt) and laptops (14%; down 2-pts).

Hewlett-Packard recently announced strong computer sales trends. But almost 70% of its sales come from outside the U.S. - where the current slowdown is likely having less of an impact - while our ChangeWave surveys focus mainly on the U.S. market.

Indeed, outside the U.S., H-P registers higher market share numbers for consumer desktops (22%), corporate desktops (20%) and corporate laptops (17%).

Nonetheless, weaker U.S. visibility clearly looks to be an issue for Hewlett-Packard going forward.