1) this depends. i *think* that your hard drive can only have up to four primary partitions, meaning that if each of those were bootable, then you could have an operating system on each, therefore four. Of course, if you have a secondary partition, it can contain any number of partitions. These will not be bootable by some bootloaders, but i *think* grub will be able to boot from inside a secondary partition (please, if any of this is wron, please somebody correct me! it's all from memory). Here's a link you might like to read, which may be somewhat relevant:
http://www-128.ibm.com/developerwork...ry/l-flex.html
I did hear once about a guy who had installed
41 operating systems onto one machine, i think. i am not sure what the record is, but i would think that comes close!
2) you can format your disk as many times as you like. there's no limit, like, you've formatted it four times, and now you've only got one go left before you have to throw it out! it's not like that at all, just wipe it and start again, as many times as you like. I could be misunderstanding your question though.
Quote:
my present problem is iam using kubuntu os
many people would say that this isn't really a problem! ;-)