Hi there Ricardo_7,
Try using different cables(SATA+power ones) and attach the drive to a different SATA port or another system.
In case the issue persists, you will need to contact a data recovery company(as some of the guys suggested) in case the data is really important. Most of the HDD manufacturers offer their own data recovery services or have some sort of data recovery partners. It would be best to check that out. In case you are interested in price, etc. etc., I believe the guys over there should be really helpful.
In case you decide to do that, it may be a good idea not to try some DIY methods that could further damage the drive.(freezing is one of them)
D_Know_WD