please help

sorry for the undescriptive title.

My problem started as the computer would crash and turn off randomly and became more frequent. Strangely, AVG also suddenly would say that the updates were old no matter how often i tried to update them. Also, I could not system restore, it would just come back after reboot saying the system could not be restored.

So, i came here and began to do everything in the READ & RUN ME FIRST. Malware Removal Guide thread.
When it came time to do the combofix.exe part i had/have more problems.

Im not quite sure if it actually ever finished. But now, when trying to start the computer it goes to the screen that gives options (Last Known Good Configuration.., Start Windows Normally, Safe Mode, etc..)
Then it goes to Check Disk and goes through it and then just turns off and restarts again and continuously does that over and and over.

Before combofix, i was just having a problem with a crashing computer. Now it wont turn on at all. If anyone can help me it would be extremely appreciated!