HELP! I can't root my samsung galaxy s3

[jclopez24]

I rooted my s3 and it was installed perfectly. i followed everything on net about the odin and everything, and its says passed. the reason that i wanted to root my phone was to downgrade my my s3 to ics because jellybean makes my battery phone drain easily. Then i followed everything on how to downgrade the android version, it was rebooted, factory reset and everything but it still in the latest version!. Due to that failed process, i rooted again my s3 , and it says failed and
<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)
also it doesn't recognized my phone in ODIN when it was on download mode. but when i open my phone normally the odin recognized it.

and when im on download mode on s3 it says,
ODIN mode
product mode: GT-I9300
CUSTOM BINARY DOWNLOAD: NO
CURRENT BINARY: SAMSUNG OFFICIAL
SYSTEM STATUS: OFFICIAL

and when i checked to a root checker it says,
this device does not have proper root access.

PLEASE HELP ME.. i wanna fixed this.
thanks in advance

 

[meyerweb#CB]

Odin is very sensitive to connection quality. Try rebooting the PC. If you're using a USB hub, switch to a USB port on the computer. Try a different USB cable. If none of that works, try reinstalling the Samsung drivers on your PC.

 

[pravin_bhudiya]

download Quick root from here : Quick Root V 4.1 - Download - 4shared.

 

[Candace Anderson1]

I tried but i was afraid beause it said it had a virus

 

[Candace Anderson1]

I have spent forever watching Youtube and following it. It says on the computer that is was unsuccessful, that was on safe root. Then I tried towelroot, my phone will not open the site and my computer will not open it either. If anyone knows please tell me before i lose it. I have a Samsung Galaxy S3 Thank you