Using KMSpico for Windows activation can have several consequences. Firstly, your system may become unstable or vulnerable to security threats if the activator includes malware. Secondly, Microsoft regularly updates its activation methods, meaning that tools like KMSpico may stop working after updates, leaving your software unactivated. Additionally, using unauthorized activation methods can lead to loss of access to updates and support from Microsoft. Ultimately, relying on such tools can lead to a less secure computing environment.