Can't flash modem !

Hey, i'm in trouble again. I should stay stock and do nothing to my phone, anyway, that's what was in my mind when i flashed a stock 5.0 firmware from Russia ( i'm from romania ) . Now wi-fi wouldn't switch on and mobile network doesn't work. ANYWAY, i tried flashing several modems, but i end up everytime with a "fail" error in odin, there is the log.
<ID:0/003> Added!!
<ID:0/003> Odin v.3 engine (ID:3)..
<ID:0/003> File analysis..
<ID:0/003> SetupConnection..
<ID:0/003> Can't open the serial(COM) port.
<OSM> All threads completed. (succeed 0 / failed 1)
<OSM> All threads completed. (succeed 0 / failed 0)
<ID:0/003> Removed!!
<ID:0/003> Added!!
<ID:0/003> Odin v.3 engine (ID:3)..
<ID:0/003> File analysis..
<ID:0/003> SetupConnection..
<ID:0/003> Initialzation..
<ID:0/003> Get PIT for mapping..
<ID:0/003> Firmware update start..
<ID:0/003> SingleDownload.
<ID:0/003> modem.bin
<ID:0/003> NAND Write Start!!
<ID:0/003> Transmission Complete..
<ID:0/003> Now Writing.. Please wait about 2 minutes
<ID:0/003> FAIL!
<ID:0/003>
<ID:0/003> Receive Response from boot-loader
<OSM> All threads completed. (succeed 0 / failed 1)
<ID:0/003> Removed!!
my baseband : is XXUHOD4.

Oh, help me fix this please, i won't do any changes to my phone, everytime i'm doing something "bad" i spending hours to repair it and end up posting a thread there, it's frustrating i mean that was supposed to take 10 min to flash the ROM and then i could go to sleep but i spent 3 hours, everytime happening the same time. Hope you get why i'm so frustrated, anyway, appreciate the help :)