[GLLUG] OT and out of area: How do I find a reputable data recovery service for a Win 7 m/c?

[John Southall IMAP]

Hi,
Please forgive me, but I don't know who else to ask.
This is for the Midlands, not the London area.
How do we find a professional data retrieval service? What should I look 
for?
We need to unfreeze a Win 7 laptop, or at least extract the data files.
We suspect that it is malware rather than a hardware problem.

John