Check this out, Norton IS slow! Over on ThePCSpy they take a look at how different software effects the Windows boot time. Here's their worst 5 pieces of software they tested:
Not surprisingly Norton slows the machine down by 58% adding 43 seconds to the boot time, for more details on the results and the other software tested check out their article itself.
How many millions of man hours have Symantec wasted with their utter bloatware?