Easiest way might be to find a Linux magazine in the local newsagents/supermarket promising a "Live CD" (or DVD, assuming you're not stuck with a CD-type optical drive) on the cover or inside. Stick it in, boot up on it (acccept defaults, assuming you avoid any actual installation options, although as you're starting from scratch that wouldn't hurt either
) and although it will change slightly between distros, find the "terminal" (command prompt, might be called "kterm" or something else with "term" in it) in whatever Start-Menu equivalent it has (might be under "System") and type "gparted" and enter. You then get something that's a GUI partition deleter/mover/creator/resizer/reformatter that you should be able to handle with a few clicks in the obvious places. (YMMV, but I really don't think you'll have difficulty at that stage.)
Most distros will have gparted (and there's a distro that's essentially "boot direct to gparted", but I don't know if you're comfortable creating your own bootable CDs). If it doesn't appear to exist, there are less graphical options that do the same job (sfdisk, cfdisk) one or both of which are sure to exist on any distro not ridiculously locked-down, but are terminal/command-line based and a bit more awkward. They do have internal and external help information you can refer to, of course, but we'll cross that bridge if you get to it, I think.
I don't know if you also need to do a FIXMBR-type operation on your disk, BTW, but let's leave that till later if the above doesn't sort everything out.