I have done this and it is fine... a cheap KVM switch is about a £10
but i've got a spare PC - has Bob? I don't now use it for switching
between ubuntu and windoze... rather between my main PC and test
machine.

I still need windoze for an app that i couldn't get to work on wine
and a windoze only scanner [i like it and when i went to buy a new one
it was faulty - so i stay with what i've got!]. I found the best dual
boot arrangement was to have the two OSs on separate hard drives. To
speed up loading windoze why not consider a minimum installation. On
my machine i'm about to junk XP as it takes so long to load and put on
win2k - bit for me it is for non internet connection so i don't bother
about malware/virus protection.