My mrs' dad, in his infinite wisdom, handed his laptop over to a nice gentleman in India (via teamviewer) who promptly installed some lockscreen ransomware on it 
I've been trying all day to clean it - easiest way probably would've been a format and reinstall, I was trying to avoid that as I don't have a windows CD or his key (being a Dell I'm presuming there's a recovery partition?).
Anyway, all the Windows repair options didn't work (startup recovery, safemode, system restore etc) so I got into boot discs (USB). I've tried BitDefender rescue disc which connects to net and updates and scans but finds nothing. I've tried TrendMicro's ransomware tool but it wouldn't connect to internet. Also tried Hitman Pro but that likewise wouldn't connect to internet.
I'm able to access the HDD using the bitdefender disc (Linux) - don't know linux but was hoping there's something else I could try? I tried running the Hitman Pro from Linux (as the net connection works with that) but it obviously doesn't work with a windows program.
Been at this all day, any suggestions?

I've been trying all day to clean it - easiest way probably would've been a format and reinstall, I was trying to avoid that as I don't have a windows CD or his key (being a Dell I'm presuming there's a recovery partition?).
Anyway, all the Windows repair options didn't work (startup recovery, safemode, system restore etc) so I got into boot discs (USB). I've tried BitDefender rescue disc which connects to net and updates and scans but finds nothing. I've tried TrendMicro's ransomware tool but it wouldn't connect to internet. Also tried Hitman Pro but that likewise wouldn't connect to internet.
I'm able to access the HDD using the bitdefender disc (Linux) - don't know linux but was hoping there's something else I could try? I tried running the Hitman Pro from Linux (as the net connection works with that) but it obviously doesn't work with a windows program.
Been at this all day, any suggestions?