You can use similar programs eg Open Office instead of MS Office, Firefox instead of IE, Apache instead of IIS
You cant run a window exe files on linux natively, however you can use WINE (like an emulator for individual win programs), or system emulators like VMWare, bochs, Qemu.
You can get the Linux OS in differenent ways:
The main ways are
- Magazine Cover Disks
- Downloading ISOs via http/ftp
- Downloading ISOs via bit torrent
A good site to start with information about the various distrobutions is
distrowatch.com
You
do not have to remove everything off your computer.
To run linux you could use emulators such as bochs, VMWare, Qemu
This method is like using a SNES emulator.
The second option is to download a live CD such as
knoppix . With a Live CD you put the CD in your drive and reboot. You will get a working version of linux and once you are finished, you pop the CD out, reboot and windows comes up.
Id recommend this method for a beginner.
The last option you can do so you dont have to format your HD is to set up a dual boot system.(this method has a risk of dataloss)