Questions: Installing a new OS on old laptop and wiping data off SSD

[Kogi]

First off, I have Windows 7 installed on my new PNY Optima SSD(about 30GB used because I just installed). I am thinking about installing Windows 8.1 on my laptop because I'm having trouble with my product key on Windows 7. I have the key installed on my old hard drive but it comes up as invalid on my SSD(I had to use a program to figure out my key since it wore off the sticker).

 

1) Can I just plug in the USB bootable drive with the OS while the data is still on my drive and run the Windows installer?

 

2) Should I wipe the data off my SSD before I do a clean install of Windows 8.1 or any other OS?

 

3) Will wiping the data off my SSD affect the lifespan/performance of my SSD?

 

4) How do I cleanly/safely/securely wipe the data off my SSD?

 

 

Sorry if some of these questions sound dumb but I've only recently been interested in computers and I've mostly been researching hardware. 

 

 

-Thanks

[LogicalDrm]

1, Yes. The installer will ask what to do when it finds previous system. Options are to format or create new partition for second system (dual boot)

2. No need. You can format SSD withing windows installer.

3. No.

4. Easiest is the format tool with windows installer. I'm not sure what you mean by secure. But if you are going to continue using same drive yourself, formatting is best solution.