I'm not sure if it would have made a difference, if you had included which operating system your friend is running. OR the name of the malware/virus. Although, it might have helped.
When researching the issue, did you read the sticky at the top of the AVG Forum titled, "Common Reasons Of PC BSOD"?
If there were BSOD issues specific to Dell and/using AVG 9 (after a malware/virus infection) I don't feel it was made obvious at this forum. With the exception of a handful of cases, I haven't read about it elsewhere, either. But I'm only one person. Perhaps, other's might be aware of the issue, with the combination you spoke of. What you might want to do is pose the question at our Dell Forum. Or possibly our AVG Forum.
You're welcome to read the threads I found at the AVG forum. In the scheme of things, I find them of little significance. Certainly not worthy of qualifying it as a "known issue".
AVG Related BSOD?
AVG 9 Is Crashing Computer - A 4 page thread with posts referencing (blaming) Dell, Windows 7 and AVG itself.
Crashed Dell, Finicky HP After AVG 9 Update
Dell System Crash (BSOD)
Best of luck..
An acquaintance of mine recently received a BSOD on her computer some point after AVG 9.0 Free Edition detected malware/virus on it. (Not sure of the exact name of the offending file at that moment.) I did some research on the issue so far and noticed a few people with BSOD issues after putting AVG 9.0 on a Dell computer. (She has a Dell Dimension 2400). I was wondering, are there any known issues with AVG 9.0 and Dell computers? Is it something as simple as a driver issue maybe?