Look at the Korg Website and find an authorized service center.
http://www.korg.com/supportCall the service center and make absolutely sure they will service the MR-1 though as some service centers only work on keyboards or other Korg products - my MR-1 sat at a service center for 3 months and no work was done until I got it back and sent it to another service center.
It may be cheaper to just buy a used one though ebay (usually sell for $100-200) or get the MR-2 using the Taperssection deal ($350).
If you have files on it you need you can pull the HDD And transfer using a ZIF to IDE cable and IDE HDD controller or external enclosure. If you are not comfortable doing this yourself there are a number of people on this site who can do this for you.