Reformatted a partition without deleting it, did it get rid of the virus?

[rhfish]

Hello,

I am pretty sure I had a virus/keylogger that my antivirus software was not detecting. So I ended up reinstalling Vista.

When I was in the installation options, I clicked "custom", "advanced" and there were options to format partitions.

I ended up just formatting the main partition that had Vista on it. The format seemed to take about a minute. Then I installed a new copy of Vista on that partition.

Now I am wondering if I should have deleted the old partition first, then made a new one and formatted it.

Would it have made a difference?

Would formatting without deleting get rid of the virus?

Also, I have a dell XPS laptop that came with MediaDirect on its own partition. The Vista setup did not allow me to reformat the Media Direct partition. Does it mean then that the virus could have survived there?

Thank you