Do you mean "Ubuntu" and not "ubunto"? Just making sure, caught my eye..
Yeah better check out how much free space you have left on your C-drive when you boot Windows. There should be plenty (several hundred megabytes for example) or you may find that Windows is swapping the space and starting to choke because it can't page. Also make sure you have enough free RAM.
Like said, other operating systems don't affect each other in no way. Why? Because unless you boot the other OS, it's just a bunch of files on another filesystem on the disk. The files don't do anything unless you make them. I don't think rebooting should either have anything to do with the matter, but then again, quite a few people seem to complain about having odd effects after rebooting from another OS.
Don't be afraid of the console (or terminal emulator for that matter), it's not a dark dungeon. Well of course it is, but just as long as you think so. Visit linuxcommand.org and things should get enlightened a bit
Another thing is that after using Linux, if you have sufficiently RAM and somewhat new CPU, you may well feel Windows is slow. I did. You don't notice it if you sit there 8 hours a day, but if you get the feel of something faster, it does feel slow. Like if you owned a cheap Toyota, drove it happily 20 years and then one day tried Ferrari for a few hours - when you go back to your Toyota, it just might feel a bit slow. And of course it can be just the other way around with these two operating systems.