the bluetooth device disappeared

I was working on my iMac and after restarting once, the magic mouse and magic track pad lost the gestures. I could use them but without any gestures such as scrolling up and down, changing from a desk top to another one, moving from 1 page to the other on a web site etc.

Then I checked the Bluetooth icon, that was not clearly visible anymore and I get the info that the hardware is not installed.

This happened some days after I have updated the OSx software to the new Yousemite.

Instead of the usual Bluetooth icon that used to be black, after this problem came up I see a sort of "wavy snake" across the Bluetooth icon.

Checking some forums in the internet, I found in one of them a table of troubleshooting cases related to Bluetooth and I saw the same indication on the icon that I noticed on my iMac. The suggested solution was to remove all usb devices and restart the computer. Which I did without success.

I still have the icon with the snake on it and the bluetooth devices work but with non gestures at all. This makes my life quite difficult while working.

I saw some similar cases related to Mac pro but not iMac. And I also have noticed that the suggestion to resolve this problem was to reset the computer pressing the command, option, P and R keys simultaneously before the grey screen appears and after I hear for the second time the start sound I should release the buttons.

Could anyone come back with help on this/

Regards

Marcos (mtg7)