Confusion on bootcamp and parallels

Hi, I am a new Mac user and I am planning to install windows on my MBA because I need to run some specific software for school. I have done some reading and know that there are mainly 2 options to do so. Bootcamp or running a virtual machine like parallels, but I am still kinda confused and hopefully someone will be able to answer my question. Do I need to make a bootcamp partition first before I install parallels or I can just install parallels as a stand alone software to run windows? If I need bootcamp first, how much hard drive space should I allocate for the partition?

You don't need to partition for Windows in Parallels only for Windows under bootcamp.

What I'd suggest is getting VirtualBox (it's a VM like Parallels or VMWare fusion - but it's free).
Install Virtual Box, install your copy of Windows as a VM. Try you software out. If it runs OK you done. If it seems a little slow you may get better graphical performance from Parallels or VMWare Fusion. But if it's very slow you're better of installing Windows under bootcamp.

Either way, you're going to need a full retail version of Windows and if you have a reasonably new MBA you'll have to use Windows 7 if you go for bootcamp.

Hope some of that helps.

Thanks for your response, I will try it out first. Assuming I am not satisfy with the performance of virtual box and would like to go for bootcamp, can I still do that? Do I have to uninstall virtual box first, otherwise, there will be 2 windows running on my mac, right? One tied with vb and another one tied with bootcamp. Also, would making a partition for bootcamp at that point wipe my data on the hard drive?

So long as you don't activate you can delete the VM and re-install.

Windows 7, for instance, you don't even need a serial number to install and use for 28 days. So you can use this period to evaluate either solution.