UK activation phone number needed

Hi. Earlier today I changed the SATA mode in my computer's bios from IDE to AHCI, having read that it might improve disk performance slightly. The computer then booted fine, but is now requiring reactivation (this surprised me a bit, I thought several pieces of hardware, not just hard disk mode, would have to change before a reactivation).

Anyway, I tried to reactivate online, but this failed and I got a message saying I had to activate by phone if my hardware had changed. So I tried to do so, but then got the error message: "An unspecified error has occurred". Despite this, the activation progressed to the next stage, where a list of locations should have come up, but all I got was an empty box and empty drop down list: When I clicked next, I got the option for a toll phone number (which I really don't fancy, because I have no idea what the toll is and I have to enter and take down 108 characters), but the freephone option says it's not available.

So really I need either the UK Windows 7 x64 activation phone number, or a way round these error messages. Any help much appreciated, thanks.

Thanks a lot, the number worked. Took a long time though, glad I didn't have to use the toll one :)