TR/Crypt.XPACK.Gen HELP!! please keeps shutting down my comp

Hi.

I have a really big virus problem with my computer, i recently connected a USB pen drive which had a virus... after doing so my computer started to shut down as if it run out of battery, it doesnt even give a warning or anything it just shuts down after about 20 minutes being on, if i then try to inmediatelly turn it back on it starts to load but after the windows logo showing up it stays idle with a black screen and nothing else happens, so i have to wait around 5 minutes in order to be able to turn it back on, i've tried tu run all the software and tried to do all the procedures needed before posting but the computer doesn't stay on long enough to let me finish them so i'm not able to retrieve any log, i'm running antivir which showed me that had detected the TR/crypt.xpack.gen so i tried deleteing it and nothing, rename same result, quarentine same thing, it keeps popping up, i've runned out of ideas i have done a system restore and came back to same situation, also it doesnt let me go into safe mode , when i try to do so it simply shuts the computer down it doesnt let me go past the welcome screen on safe mode... :cry so please help me out i want to know if there is anything else that can help me before trying to format the c: drive.

thank you in advance for the help, really apreciate it.

 

[FONT=Verdana, sans-serif]Welcome to MajorGeeks.com![/FONT][FONT=Verdana, sans-serif]

Please follow the instructions in the below link and attach the requested logs when you finish these instructions.

[/FONT][FONT=Verdana, sans-serif]Read & RUN ME FIRST Before Asking for Support[/FONT]

 

Hi... I already did all of those steps my computer was able to run ccleaner and did the basisc of emptying the recycle bin and all of that but when i run the other software they are not able to finish the scan because my computer keeps shutting down in the middle of it because of the virus :S so the software is not able to produce any log i've tried to run SUPERAntispyware, spybot, malware bytes, but they never finish because i don't know how to keep my computer on longer than 20 mintes, and i was wondering is there anything else that could be done??... i'm going to keep trying with the software but almost everytimes it gets to the same point and shuts down :S

Thank you for all your time and help