WD Scorpio SATA drive suddenly not detected

I've got two SATA drives - one SSD and one 2.5". The SSD is my C drive and is working fine; the other, a Western Digital Scorpio (blue I think) 500GB just suddenly wasn't detected. I tried a different SATA port, different SATA cable, to no avail. Also tried changing the SATA mode to AHCI from IDE, which resulted in no hard drives detected at all, so I changed it back to IDE.

It wasn't making any suspect noises, and was working perfectly fine right up til I shut the system down last night. Can a virus do this, or does it sound more like a mechanical failure? Anything else I can do to troubleshoot? The point may well be moot, if it isn't the power cable I'm not sure I can do anything with it. :(

Just checked, and thankfully the drive was still under warranty (I'd no idea it carried a 3-year). So...hopefully I'll be able to do data recovery thru a business, and then after that I'll be sending the dead one back to WD for replacement. This'll teach me to keep stuff backed up more consistently. Thankfully though, it's only recent scanned business receipts that I'd lose if I can't recover the data...nearly everything else is backed up. whew! (on a side note, there goes my excuse to buy a better/bigger drive... :( )

if they need to crack it open for the recovery kiss your warranty goodbye! I've got a 400GB seagate drive filled with pics and vids that's waiting for cash to get it recovered :(

actually, western digital says in their warranty if I have data recovery done, they need something on company letterhead saying so. The guy who's doing the data recovery told me all the details when I asked him, and what he said matches up with what I'd read previously in the warranty. He said he's dealt with WD before and they honor their warranties, so I should be good. Still...the recovery's costing a LOT. I'll certainly remember to back up the drive more frequently now.

What are the costs in your area for data recovery? The price where I took mine ranges from $250 to $750; mine's a 2.5" drive with a bad circuit board, so the total cost with donor drive (and barring anything else being wrong with it) is going to be around $600. I called a bigger company in LA for price comparison, and they quoted me between $500 and $1800 depending on the problem.