Currently I like Win 8.1 and it runs (so far well) since I applied the update a little while back.

Now, I install my OS's on separate HDD's of their own.

I used to have Vista, Win 7 and Win 8 (a few months ago when I bought Win 8 when it was on offer (£25) running which I could choose through the BIOS as to which one I wanted to boot up with no problems.

Recently I upgraded the vanilla Win 8 to 8.1 I found that it had somehow knackered the Vista installation, as using 'This PC' to view my drives I found that the drive for Vista was labelled 'NTFS' and any access was denied.

I found this out because I tried to boot up with Vista, and found that it wouldn't, even after the CHKDSK routines it ran, so looked in 'This PC' to see what was what, and clicking on that drive I got the 'access denied' info box.

So I just formatted that drive and left it alone for a few weeks.

I reinstalled Vista on to it's HDD yesterday, with just the SP2 pack, chipset and LAN drivers.
All other HDD's had been disconnected, as is my usual procedure.

Win 8.1 killed it and labelled the drive 'NTFS'.

Also the CHKDSK routine kicked in on every reboot, the same as before.

So, today I tried again installing Vista on different HDD (in case the other one was a bit 'iffy')..and I know that drive was OK because it was running Windows 7..which I don't like that much.

Again, when I shut down and connected the Win 8.1 HDD, the Vista drive was again labelled 'NTFS' and 'access denied'.

All is fine until the Win 8.1 HDD is re-connected, which is when it all goes wrong.

Now, I actually like Win 8.1, but I also like Vista (yes, I know I am a leper ) and just wanted the option to run them both as only Vista will work on one site I need to use, which will only accept IE8/9 32bit browsers............I have tried a couple of other browsers, but - no go.

I suppose I could re-install Win 7, as I think it will run with Win 8.1 installed, but, I am not keen on it.

Has anyone any ideas as to why when I try to run two different OS's (on separate HDD's) Win 8.1 will kill it ?

Sorry for the long post, but was just trying to give all info...