Share your experience!
Last night my phone power switch stopped working. If it's off I can't turn it back on. If I charge it, it comes on, but then I can't turn it off (it will power down after a couple of minutes of no usage though). I've reset my phone, I've removed and put back in the sim card, I've tried the volume up-power button combo, and I've called Sony support (it's from Taiwan so Sony won't touch an out-of-country model). Help!
Hi @CheetahWIG, welcome to the community, I am sorry to hear about this 
Is the phone in a case or anything that may interfere with it?
If not, then then you can try a software repair using Xperia Companion, but likely it will need a physical repair. I recommend you contact the retailer you purchased the handset from.
(it's me CheetahWIG):
The US Sony support team stopped mid-help to inform me that since my Xperia is from Taiwan (I bought it through a US reseller) they can't help me any further, and I need to contact Sony Support in Taiwan. They gave me a link, which doesn't allow chat, but has a (non-working) phone number and an email link. I sent an email 4 days ago and haven't heard anything back. Now what?
Try emailing them again.....but as Sony do not offer international warranty you will be asked to send the phone to them. Only other thing you can do is contact who you purchased the phone from & depending on how long you have had it they may have some form of warranty/exchange, or you can look into getting a 3rd party mobile repairer to look at the phone but as soon as they open it up your Sont warranty is void.