USB hard drive spooling issue. confused data tables?

I have a 320gb Toshiba 3.5” USB hard disk (with external power source) that I’ve been using for a long time now with no problems.

A couple of days ago I accidentally turned the power off before windows had fully shut down, and now the drive will not be recognised. I’ve tried the whole uninstall drivers thing but nothing worked. Now it merely ticks over very quietly as soon as I switch it on. Drive fried? I’m not so convinced (although ticking means damage right?): the problem here is different from most of the recovery advice I read, the data is all in tact. The reason I know this is I’ve actually gotten the drive to work perfectly fine twice by fluke, and once it was spooled up and whirring away, all was fine, no data loss or anyhting until it was switched off.

Each time it worked (twice so far), it had been on, ticking away, for a bit of time (about an hour 1st time, about 20mins second). Each time the drive spontaneously started to spool up and work happened the same way; I had just exited spinrite to change the bios virus setting, and while there I double checked the hard drive recognition in the bios (tinkering about, not doing much really)…suddenly the drive would spool up and work.

When I removed the drive from the casing, and attach it directly to my motherboard to read it in spinrite, it was recognised instantly. I ran option 2 on spinrite, and it came back with no errors at all. Drive back in casing > same problem as before. Just tried the fluke method that worked before and it doesn’t work, so no idea what made it work before.

I read the following on another forum, and it sounds exactly like my problem:

“Hmmm, there is a lot of discussion of total disasater here, dead HDD, etc. Then part way through you tell us the final action before failure was that you unplugged the external HDD (on USB conncetion) without going through "safely remove", etc. What you may well have done is simply to disconnect while the OS still had not finished writing info to the HDD. In that case there would be no hardware failure - just some very confused data tables in the Directory and FAT structure on the disk. If that's the case, some of the commercial disk-fixer software, like Spinrite as suggested, should be able to solve that problem so that you can use the disk again, plus restore almost all of the data stuctures so that the files are useable. Go with this software-fix approach first. I don't know whether it will make it any easier to pull the HDD from its case and hook up (via adapter) directly to the on-board IDE controller.”

Basically, the problem seems to be with the initial spool up of the drive. Do any of you absolute legends have any idea what exactly I need to do to fix it as I've already tried spinrite with no luck? Perhaps I'm using the wrong setting?
If I can get it working again by fluke (or connect it direct to mainboard), would formatting it solve my issues? (I’ve already backed up the important data last time I got it working)

Thanks!