Hi!
I am a newbie.
I just purchased a MacBook Pro 2.4GHz 3 weeks ago, pre-loaded with Mac OS X v10.7.2 Can anyone here help me out? My problem is that I don't seem to be able to open my desktop folders and Macintosh HD by double-clicking as I always did with Mac OS Tiger. I have to resort to using keyboard shortcut Command O to open my folders.

Go to System Preferences and check your settings for the input device (Trackpad?). It may be set to a level that is not responsive enough for you.

Thanks Ira L.
I did check the Trackpad settings over and over but to no avail.
This is what I found under Finder Help:

In the Finder
If the item is on the desktop or in a Finder window, double-click it.
If the item is in the Dock, or in a Finder window sidebar or toolbar, single-click it.

The single-click works just fine for items in the Dock, except for the double-click of desktop folders and folders within folders which are not responding.
I remember the double-click was responding when I first got the MacBook Pro
till 2 days ago.

I wonder if a single click on a folder or file icon registers by selecting that item. If so, did you by any chance check the double-click interval settings of the trackpad (Apple menu/System Preferences/Hardware/Trackpad*)? If not, see if changing that setting improves things.

*) Since I do not use Lion (where it may be different), I provided the path as in older Mac OS X versions.

You can always trash finder preferences. First, enable view for the user Library. In the Finder menu on top of the screen right-click on Go (or control-click), navigate to Library and open it. In the Preferences folder, locate the file com.apple.finder.plist and drag to the desktop. Log out and then log in back. The file will be re-created. See if this helps. If yes, trash the old preference file. If not, the same way you can trash the trackpad preference file.

Your path is correct for Lion.

Just curious,but couldn't the same thing be accomplished by using com.apple.desktop.plist

Thanks alternaut.
You are absolutely right, my trackpad setting for double-click interval was set way too fast that it didn't respond. O well, I am not savvy enough for the new OS X Lion, still being so used to OS X Tiger which I kind of taking things for granted as far as setting-wise.

Thanks for your help macnerd10.
Problem solved. I took your advice and trashed away the old trackpad preference file. I was unaware that the user Library folder was hidden and so I searched for Finder help to navigate to Library and managed to open it holding down the option key. My gosh, all the trial and error - silly me.

An excellent source of information is Mac OS X Lion: The Missing Manual by David Pogue. Even though I am not yet using Lion, I bought it for general information before I take the plunge. I have used all his previous books and can vouch for their worth.

You may think that way, but it looks to me like you're doing well enough!
And while on the topic, I'd like to recommend you leave the 'dissing' of yourself to others. They're way better at it...

Like!

It's certainly a pleasure to join FineTunedMac. You guys are cordial and helpful, I feel much encouraged. My sincere gratitude to all.

I have POGUE's for "Lion." It is every bit as use-ful and use-able as the previous volumes in the series.