Using Windows 7 Pro. I got a Windows 8.1 License with a setup .iso file. I want to setup (upgrade) Win 8.1, but before, I need to verify something. I have Ubuntu installed side by side with Win 7 (Win 7 installed first). The current boot (grub) is of Ubuntu because it's the last one installed. My question is : "Will installing Win 8.1 overwrite the boot (grub) of Ubuntu? if it's the case, Will Windows give me (as an alternative) the choice of starting Win 8.1 or Ubuntu?"
Because in fact, my current PC came with SLED installed, and I need Windows of course, so when I installed Win 7, I lost access to SLED (grub has been wiped) and Windows started directly. That's why I installed Ubuntu after Windows 7 because I need at least one Unix OS installed side by side with Windows.
Looking on the web is saying yes, the grub will be lost. I need to confirm from you here, because, any error will cost me a very big pain (reinstalling the tens of apps that I have after installing Win 8.1 is enough), and Thanks in advance.