I installed Linux on to the laptop.
You run no risk, even if some Windows malware remains on the disk, it will not be able to infect a Linux install.
I've not installed Ubuntu recently, but I did recently install other distros like Red Hat and CentOS. When you install these over an existing OS, they ask if you want to erase the existing partitions and create new ones. And they use another filesystem on the partition: ext3 in stead of Windows' NTFS.
I guess that your Ubuntu install did the same. You erased the existing partitions, and reformatted them with another filesystem.
If there is malware surviving on your disk after this, it has to be malware that targets the Windows kernel. You are safe, because you don't have a Windows kernel anymore, you have a Linux kernel.
There is no malware in the wild that is cross-platform Windows/Linux kernel.
Edited by Didier Stevens, 13 September 2011 - 02:28 PM.
SANS ISC Handler
Microsoft MVP 2011-2016 Consumer Security, Windows Insider MVP 2016-2018
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