Thank you for your prompt reply. It came back just as I had expected....
To answer some of your queries:
1) I have been using the system for a very long time and have also had viruses infected, though I have been able to remove them and continue using my system. However, now I felt that I need to format my C: drive as it has taken up too much space and there have been many installations and removals of softwares on the same.
2) I had multiple logical partitions already on my single hardrive and hence thought that I would move all my required data to these drives and then only format C: to optimize the performance of my PC. I also decided that the newly installed OS will be kept totally separate and my installations and other files and folders organized separately on different logical partitions.
3) Hence I went ahead and installed a new copy of Win XP on another partition with the thought that once I check and find that it is stable and I am able to login and access it I will go ahead and format C drive and rearrange the partitions to use up this reclaimed space and start using my new OS.
4) The whole idea was to move over to a new OS with minimum downtime and without the use of another external HDD or media for BackUp as I have none. My understanding was that if I format C: drive the other partitions remain unaffected and hence I can safely have all my data on the other partitions available to access and use from the new OS.
5) I used "EASEUS Partition Master 4.0 Home Edition" to create partitions and do the above process. It has many options and one of them is to set the other OS partition as Active to begin booting up from that particular partition and OS. It also allows you to rename or assign Drive Letters to your partitions. Hence, I thought I could format the old partition (C:) and assign some other letter to it and rename my new OS to C: from G: and felt the transition would be smooth.
Do you think this will work ?? Please advise....