Updating Records in SQL database

I have a client who has a SQL derver database. They have reecently moved some data files to a new server. My problem is that within one of the SQL tables is a list of records that are pointing to files on the old server. E.g. w:\msoffice\word\myname\client\file.doc or w:\msoffice\othername\client\file2.doc.
I need to change the first part each of these records and retain the later part e.g. o:\word\myname\client\file.doc. There are 5,000 records in total.

Does anyone know how I can do this within the data
My limited knowledge of SQL doesn’t go this far

Thanks