USB key not found

i have downloaded proton compiler version 3.5.0.7 and mplab version 8.50 from http://melabs.com/support/mplab_old_versions.htm.
proton compiler gives the compiler error of missing USB key or security key not found.
to solve the problem i copied sparkey.sys fie from PBP folder to C:/Windows/sys32 folder but the problem is still there.
for this very reason PBP cant be integrated with mplab either.
could someone tell me the possible solution?

Several things.

Are you talking about Pic Basic Pro (PBP) or proton?

The only version of PBP that can be downloaded is the demo version, not sure about proton.

So what are you using and is it legal?

its not PBP its proton compiler infact.though i did have the demo version of PBP but it gave the same compilation error.

When you purchase the compiler you will receive the KEY.