Im going to be building a new computer this summer and will be moving my hard drive over from my current one. Is it best to reformat and do a clean install of windows after rebuilding or will it be alright to transfer it over without deleting everything. Im trying to figure out if im going to need to invest in an external prior to building the system.
 
If i didnt would it still be reasonably stable for a few months? I am going to reformat the drive and do a clean install of windows 7 when it comes out on MSDN and i just want it to be stable for the month or two between its assembly and windows 7