who remembers chkdsk
/mbr? Why did miscrosoft take it away? It was that easy to rebuild the master boot record.
I have a feeling that testdisk, that wondrous tool, might rebuild an mbr, but, if there is any doubt about ever going back to pure windows without doing an entire windows installation, then better use a master boot record backup tool (testdisk? I think it will).
I'd take issue with "messes with". Just with the choice of words, that is

.
If you want, you can make (but not format) your linux partitions in windows before you start installing ubuntu, but the ubuntu partitoner understands ntfs as well as linux filesystems. In fact,i have just been using gparted, on a live boot disk, to shrink and move partitions on a pure winxp machine, which you cannot do with winxp tools.
To boot an os, the bios is going to look in a particular place, so grub has to work from the mbr. I guess that, if pure-windows is wanted again, it could boot into windows by removing all its other options.
Otherwise, those linux partitions can be removed just like any other partitions. Maybe window's own disk management would do it: If not, the gparted live-disk tool certainly would.