Time Machine crashes every time

Have changed the drive I'm using for Time Machine, so had to do an initial backup around 70 GB in size, every time I do it Time Machine gets so far with the backup, sometime 1 GB, sometimes 30 GB, then just stops. It says it is backing up but the progress bar stops and the data traffic lights on the hard drive stop flashing.

I am unable to stop the Back Up, or force quit or anything. The more I try, the more locks up until I have to restart the MacMini by holding down the power button.

I suppose it could be my drive, but I have been using it for about 9 months for storing movies and had no problems. It is a WD Scorpio so should be reliable.

Anyone else experiencing this? I have tried formatting the drive and starting again but not sure what else I can do. Is it worth trying a hard reset of the MacMini, if so, what's the best way?

Ok, found this in apple support:

Some hard disks ship with a Master Boot Record (MBR) partition type. For these disks, you will need to change the partition type and erase the disk so that it is supported by Time Machine.

1. Open Disk Utility.
2. Click the Partitions tab.
3. From the Volume Scheme pop-up menu, choose the desired number of partitions.
4. Click the Options button.
5. Select a new partition scheme:
* Use "Apple Partition Map" partition scheme if the disk will be used with Time Machine and a PowerPC-based Mac.
* Use "GUID" partition scheme if the disk will be used with Time Machine and a Intel-based Mac.
6. Click OK.
7. Click Apply.

Once the external hard disk is repartitioned, select it again in Time Machine preferences and use it for your backups.

So, have done the above and am now backing up again, will let you know if it works...