Caps lock doesn't work on vista

Sounds like the keyboard could  be faulty.
have you tried reinstalling the keyboad drivers?
CT

Yes. Also tried to modify registry.

When you tried Regedit did you by chance see any of this: Disable Caps Lock Key in Windows Vista
The caps lock key is one of those remnants of another age of computers, back when people used to shout at each other more often. Since it's not entirely useful anymore we'll learn how to disable it. If you aren't interested in the explanation you can skip to the bottom for the registry files.

Windows doesn't have a default setting to allow for disabling the key, so what we have to do is re-map the key to something non-existent so as to completely disable it.



Here's the format of the binary data, with the important parts in bold and various colors:

00000000 00000000 0200000000 00003A00 00000000

Here's how it works:

The first 16 zeros are just there to waste space.
The "023 in bold represents how many keys you are going to re-map plus 1. (It really represents the length of the data, but whatever)
The orange bolded "00003 is the key we actually want Windows to map TO, which in this case is nothing, or 0.
The blue bolded "3A003 is the key we are mapping from, in this case the caps lock key.
The next 8 zeros are there to waste space as the null terminator.
You can map between multiple keys by incrementing the "023 and then adding another of the colorful bold blocks in the middle. The 3A00 in the mix is the scan code.  For example, if you wanted to disable the caps lock key and then change scroll lock into a caps lock key:

00000000 00000000 0300000000 00003A00 3A004600 00000000

Now that you've learned how these things work internally, you can download and extract the zipfile which contains the following files:

ChangeCapsToControl.reg Changes Caps Lock to be a Control key
ChangeCapsToShift.reg Changes Caps Lock to be a Shift key
SwitchCapsToScrollLock.reg Disables Caps Lock and swaps Scroll lock to be Caps Lock
KillCapsLock.reg Disables Caps Lock
DisableKeyboardRemap Uninstalls the preference by deleting the key

Once you've applied one of these registry files, you'll have to reboot your computer for it to work. To uninstall, you can use the uninstall registry tweak, or you can simply delete the Scancode Map key entirely.

Download Keyboard Mappings Registry Tweaks

Pcobiwan wrote:  "The caps lock key is one of those remnants of another age of computers, back when people used to shout at each other more often. Since it's not entirely useful anymore we'll learn how to disable it."

Oh, boy, Pcobiwan... I can't believe you wrote that.  Well, I'm gonna' shout at you right now, and I'll barely touch the caps lock key.  Just watch...

I'm sorry, but I just can't let it slide by.  The caps lock key has been present on QWERTY (and pretty much all other layouts of) keyboards since the earliest days of old mechanical typewriters... long before there were computers, or an Internet, or chat rooms, or forums, or texting... or even you, I suspect.  Its purpose has nothing to do with typing things in all capital letters in a chatroom as a means of e-shouting at someone!  It had function and purpose before that, and will for long after... that is, if people like you don't mislead others into believing otherwise.  

Caps lock is routinely used in all manner of personal and business typing of real and important things... reports, letters, emails... as a means of typing titles, or headings (or sub-headings).  Cops and lawyers nearly always type the names of persons (subjects, witnesses, victims, etc.) in all capital letters in reports and other documents.  Some computer programs, to this day, require and will accept only all-capitals.  The US Postal Service's machines that scan the fronts of envelopes and read the addresses do it better and faster if they're in all caps.  And, of course, though it's a violation of netiquette, people use all caps to "yell" at others in chatrooms and other such places.  The list goes on and on...

...and locking caps just before typing text strings intended to be all capitalized , and then unlocking caps afterward so that normal typing may resume, is the way that many, many, many, many, many, many, many (am I making my point about just how many?) people do it.  Routinely.  Every day.  Everywhere.  There isn't a typing teacher alive (or dead) (or even as-yet-unborn, I'll bet) who wouldn't absolutely FLIP over your assertion, here.  It's ridiculous.

The attitude smacks, to be candid, of the sort of narrow viewpoint which someone (someone most likely very young, I dare say) who has spent entirely too much time texting in both shorthand and all lower-case letters would have.  Such as they get into forums and other places and insult readers by typing "u" instead of "you" and never capitalizing anything.  It just grates on those who love and respect the language, and who have an education.

I'm sorry to take you to task for this, but I don't want to see anyone around here misled.  If I get thrown out of here for it, then fine.  As I think Graucho Marx once said, I've been thrown outta' better places than this joint.  And I've been (proudly, I should point out) getting thrown out of computer stores for years because I interrupt salespeople whom I overhear blowing smoke up the butts of hapless customers, and call them on their bad and misleading information... so if it happens here, too, then so be it.  I'll live.

Teach 'em how to disable caps lock if you want.  That's a perfectly legitimate thing, if someone really wants to know how to do it.  But don't cite as a good reason that caps lock has become superfluous, because nothing could be further from the truth... just as yours couldn't be further from a good reason.

Ummm - I didn't write that comment.  It was part of something I copied ;)  I'll be sure to edit more closely next time.

I tried  everything that was mentioned above except boot laptop from CD to understand if it hardware and software error. My fault
Thanks to all for your help