Hi Aju, Is this your first time pairing the QC35 to the computer, or Was this working previously?
If this is the first time and you are unable to pair, you may need to update the drivers fro yoru computer's Bluetooth antenna. This can usually be done by visiting the manufacturer's support website for your computer and looking up the model number.
If it was working previously before this error came up, try instead removing (deleting) the headset from the Bluetooth devices list in windows. Once gone, you can hold the power switch on the QC35's to the Bluetooth symbol for 15 seconds until it announces that the pairing list has been cleared. Then take the same steps you used originally to pair the headset and computer together again. See if the fresh connection works better.