Windows 7 Boot Loader

If you are saying you have two Os on the hard drive, and you get the option in windows 7 boot loader to select what Os to boot what`s the problem ?

If you did a clean install/ format of the hard drive then no.
Windows 98 would simply not exist due to the format.

If it is a multi boot through windows 7 boot loader.
The load up windows 7, in the search box type : msconfig.

click on the boot tab, it should show two os if dual boot.
Hi light the os you wish it to boot from and click on the set as default button.
Save/ apply exit and restart.