Filevault home directory encryption '22 minutes remaining'

Hi all,

I'll try and keep this as informative as possible.

I'm running snow leopard, all update to date with latest patches. (17" MBP)

Im running a 500gb harddrive.

Last night I enabled Filevault and selected the secure erase option.

It quickly reached 30 minutes remaning, so I went ahead and went to bed, leaving it to do its stuff.

When I got up today, the screen was asleep, I pressed the space bar (trackpad did nothing).

It woke up right away, however on the screen it read '22 minutes remaining' at the 'encrypting home folder' screen.

(like this: http://www.wap.org/journal/encryption/timeremainingsm.jpg )

The progress bar is about 50%.

I monitored it over the course of 45 minutes and nothing changed. The progress bar did not increase, the time reamaining did not decrease.

There is a spinning progress circle on the screen & the mouse does not appear at all.

The hard drive sounds like a hive of activity, as if something is happening, but the visual output does not indicate this.

Does anyone have any experience with a similar situation? And if so, can you reccommend the best course of action on my part?

Many thanks in advance to all for reading this and if any assistance can be offered!

Regards

Ross