Windows 7 Multiple Uses?

I was planning on building my first pc and read some reviews online for ssd's and using them for boot drives. Some people say that there ssd's crash after only a couple of weeks and I was wondering if I install windows 7 on a ssd and it crashes do I have rebuy windows or can I use the disk more than once?

You can still reuse the keys as long as it is one machine active per key only.