How to troubleshoot BSOD after removal of virus?

Possible Duplicate:
What to do if my computer is infected by a virus or a malware?

I'm battling a virus right now, I have a Windows 7 ultimate, 32 bit, Using AVG virus security.

It's a virus which infected my hotmail account, spamming my contacts with a link. I changed my password, my security question and the one of my Gmail too, just to be safe. I downloaded Microsoft Security Essentials, uninstalling AVG in the process.

After the Install the computer asked me for a restart which I did, now when I start my computer up normally it BSOD after 1 minute of loading.

I started my computer in Safe mode with networking, scanning it fully with MSE, finding 5 threats, deleted. I cleaned my registry with CCleaner.

I still get a BSOD at normal startup.

The messages the virus has sent have a random subject generator, so It's (no subject), Re:, Re:.., Re: hello!.

I'm almost at the end of my rope here, I'm downloading Windows 7 ultimate, going to boot it on a USB and try to repair Windows.

What could I do?

EDIT1: more information about the BSOD

BSOD: Technical information:

**STOP: 0x0000008E (0xc0000005, 0x83406487, 0xAC38275C, 0X00000000)

** ataport.sys - Address 83406487 base at 83400000, Datestamp 4a5bt..