I have a Windows Home Premium 7 pre-installed with my Sony Vaio VPCEA24FM laptop. I am running pillar to post trying to find out, does this Windows install expire on some date or it is valid for the life of laptop?
Release versions of Windows 7 don't have an expiration date, so if it's a legitimate install (which it ought to be, given that it was pre-installed - check at http://www.microsoft.com/genuine/validate/ if in doubt), there shouldn't be any problem.
It won't expire in the sense of your not being able to install it; but starting January 13, 2015 Microsoft will end mainstream support, 5 years later on January 14, 2020 extended support will end. After mainstream support ends, Microsoft will stop adding any new features/enhancements(1) to the OS but will continue to provide security fixes. When extended support ends existing security patches will remain available; but no new bugs will be corrected. In the past, as the end date approached MS has occasionally closed exploits as "won't fix" if the fix would require very large amounts of work. The most recent high profile case of this was a bug in the Windows 2000 networking system that occurred roughly a year before support was schedule to end. Microsoft's justification was that fixing the bug would've required a complete rewrite of the networking code to fix (or backporting the WinXP network code, which was a complete rewrite, to Win2k).
(1) With the minor exception of customers with high end support contracts that AIUI include paying an hourly rate for MS developers to implement the feature.