Vista - Could not add the requested feature. The error is: The system cannot find the file sp

When I open my LAN properties only "Client for Microsoft Networks" is seen.If I click on it and try to install any Client,Service or Protocol I get the following error : " Could not add the requested feature. The error is: The system cannot find the file specified"
But my network is working fine.I am writing this message from the affected computer.
What's the problem?

Now I tried to follow this post:
Missing network
where a user named "Steve Winograd" said
"Go to Device Manager and un-install the network adapter for the Local Area Connection. Then, click Action > "Scan for hardware changes" to re-install the network adapter."
But after uninstalling the adapter I am not able to install it back by doing - Action > "Scan for hardware changes".The list just refreshes once and the adapter is still missing!

What do I do now?

Hi new1user and welcome to Vista Forums

Did you restart your PC? If not, restart it and you should find that the adapter is redetected when you reboot and that the driver should be reinstalled automatically.

Thanks for the reply.

Yes I did reboot my system.
But I think I made a mistake.I just now saw in "Network Connection" that the "Device Name " for my LAN is Intel(R) PRO/100 VE Network connection which I never touched .I think I removed a wrong adapter.
I remember it was something like "Microsoft tune......network connection" with a yellow exclamation mark in front of it.
currently there are only 4 adapters which appear in the list :
Intel(R) PRO/100 VE Network connection
Intel(R) PRO/Wireless3945ABG Network connection
VMware Virtual Ethernet adapter for VMnet1
VMware Virtual Ethernet adapter for VMnet8

the last 2 with exclamation marks.
How can I get back the driver for the missing adapter installed?
Should I un-install the driver for Intel(R) PRO/100 VE Network connection and then follow the same procedure to get my original problem solved?

Dwarf,
Following your instruction ,I uninstalled the driver for Intel(R) PRO/100 VE Network connection but now on doing "Scan for hardware changes" it first shows "installing driver software" but then gives the error message
"Please consult with your device manufacturer for assistance getting this device installed
Intel(R) PRO 100/ VE Network Connection failed "

I had rebooted my system several times and tried the same but with no success.
In the device manager now there appears another adapter named "Ethernet Controller" with a yellow exclamation mark ,whose properties show "This device is not configured correctly.(Code 1) .To reinstall the drivers for this device ,click reinstall driver" ,on doing so if I "search automatically" it says "the best driver is already installed in your computer" ,
and the for the other option to browse the computer it shows the error message " Windows found driver software for your device but encountered an error while attempting to install it.
Intel(R) PRO 100/ VE Network Connection
The system cannot find the file specified."

Now ,refreshing the list once I again get back the original Intel(R) PRO 100/ VE Network Connection adapter but now with a yellow mark and with identical properties as above.

What can I do now?My network is gone and now I am on a different computer.
Do I need to contact the manufacturer of the device?
Please help.

Hey, sorry I didn't realise that I started my thread in the wrong place.

And sorry for multiple posts.
I can't find the option to delete them or combine them.

Please help!

Please ignore this

It could be because you have VMware installed and the virtual adapters are conflicting and causing problems. Try uninstalling VMware and see if that helps.

I un-installed VMware and restarted my comp,several time just now ,scaned for hardware changes in the device manager but with no luck.
The VMnet adapters are gone but the network adapter still appears with an exclamation mark ,showing the same error as above.

Is there any problem with any registry entry?(a hint which I got from some other posts)
Is it possible to completely remove the driver and install a new one?
The driver version is 8.0.47.0 and it is not even anywhere on the net.