Originally Posted by MistahBungle
First, boot into recovery (the 'Volume + Power + Home Button' thing) & try a factory reset. If the problem persists, the only way you're fixing it is by flashing a stock rom with Odin.
As you can't seem to get your PC & phone to recognise each other, you need to find Hopper8's 'Odin troubleshooting' thread stickied in General, and do as many of the troubleshooting steps in that thread as many times as you need to until you get a successful flash of stock.
This is the only way you'll be fixing your phone for your 'something in two days'.
First of all; thank you so much for replying!
I tried to 'jump start' my phone. Success! (I guess?) It's in Download Mode now.
After trying Odin v1.8.5 it recognised my phone and I downloaded a normal stock kernel (is that what it's called?)
Anyways; this happened:
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> GT-I9100_XEU_I9100XWLP7_I9100XXLPS_I9100XEULP5.tar.md 5 is valid.
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/004> Odin v.3 engine (ID:4)..
<ID:0/004> File analysis..
<ID:0/004> Can't open the serial(COM) port.
<OSM> All threads completed. (succeed 0 / failed 1)
Should I try it again or do you have any other advice?