My answers need comformation now? j/k
if there is no 2nd OS. and this one he selected is the correct one, you can then delete the other one if it bothers you..
now.. if you select the wrong one, and you reboot you'll get a notice that there is no OS like it said before..
For this case, boot with floopy or another boot cd..
I recommend EBCD
In the root directory c:\ look for boot.ini remove the time selection or add some seconds.
Can't find the boot.ini? cause it's hidden....
attrib -h boot.ini
attrib -r boot.ini
attrib -s boot.ini.
to edit the file type this:
an editor will load up and you can remove the bad one or add the boot timer on again.
save and close,,
then run the three commands to unhide the file but this time dont use the - use + like +h