[Q] Problems updating to Lollipop topic

Hi,

To make to perfectly clear I am not a developer and my understanding of such issues should be classed as "novice" but I have done a lot of reading up and believe I now need to post a question regarding my problem.

Here goes...

I bought a 32gb off Amazon before Christmas which arrive with 4.4.4. I assumed after a few days of running it would update itself to Lollipop but to no avail, no matter how many times I "checked for updates". I now believe this is probably due to it being a Japanese import. I suspect this as this is on the barcode sticker and the Android with the hatch open logo in recovery has Japanese text underneath.

Anyways I posted a few questions on the Google community and they have basically told me to sit tight as the update is still rolling out. Seems to me that I could be waiting forever so I started to look at doing the manually install myself, remember I'm a amateur here...

I successfully downloaded the ADK file from Google and, even though this came with the USB drivers, I downloaded these seperatly too. I've since deleted the duplicate files.

The problem I am getting is I cannot get the USB drivers to install for when the phone is in USB debugging mode. When I put the phone into both PTP and MTP mode I can direct the driver location towards the folder and everything works OK, when its debugging mode it says they cannot be installed. I think its important to note that I am using Windows XP.

I've tried removing, restarting and reinstalling but to no avail.

Suspect its an XP thing, how do I get around this?

Thanks in advance!