Random inquiry, but my phone is doing weird things and I don't know how to fix it, ugh.

It's a Sony Ericsson Xperia Ray. It seems like it keeps rebooting when I try to turn it on. It shows the Sony Ericsson start-up screen, then goes blank and keeps looping like that. It doesn't react to anything, not even attempts to switch it off again.
Has anyone had this issue and know if there's anything to do about it?

The only advice I've been able to find is to use Sony's PC Companion client to update the phone, but it won't even register on my computer, probably since it's rebooting all the time.

Eh, I've been running around trying to find an old phone I've kept for situations like this so I can at least call people. Why do these things always happen late at night when you need to go to bed? Bleh, I better go sleep. Hope I can find something out tomorrow, I don't have money for a new phone right now, please don't be perma-dead :/