What are the differences between windows nt and windows 95?

There is no fix for the MS03-010 security issue on Windows NT 4.0 because Microsoft claims that "Due to these fundamental differences between Windows NT 4.0 and Windows 2000 and its successors, it is infeasible to rebuild the software for Windows NT 4.0 to eliminate the vulnerability. To do so would require rearchitecting a very significant amount of the Windows NT 4.0 operating system, and not just the RPC component affected. The product of such a rearchitecture effort would be sufficiently incompatible with Windows NT 4.0 that there would be no assurance that applications designed to run on Windows NT 4.0 would continue to operate on the patched system."