Saurabh,
Thank you so much for this procedure. I fixed my Dell studio1749 in about 10 minutes and works perfectly.
What I don't understand is why Dell tech support could not have told me this. I spent the better part of a day troublshooting with dell over the phone just to have them tell me to ship to depot for my extended warranty support to replace the bluetooth card. Since i told them I did not want the operating system reverted to windows 7, the depot sent it back telling me additional steps were needed to complete the action(after one week at Dell). Apparently they did not replace anything since they felt it was a software issue. Per their instructions i re-contacted tech support and went thru the whole process again only to have them say I needed to get a contract for software support as my extended warranty only covered hardware. I refused to pay for additional support and decided to live without the bluetooth until i replaced my laptop with a non-dell product. Just because I am a little stubborn I continued to search the web and came across this issue with this reply and decided to try it. 10 Minutes after finding this page my laptop is working fine in windows 8. Why did I have to go through all this and spent 10 days without my laptop working. if I had done what they wanted, reinstall windows 7 , I would still be reconfiguring my laptop.
I amstill very unhappy with dell for putting me through the frustration to get to such a simple fix which I only through luck found on my own. My next computer will not be a dell ( and I have had MANY Dells over the last 15 years).