Hi byvs,

Well, first find out "where" it's performing the CRC check
And if you find that place, then search for where it's comparing the original value with the CRC'ed value
This can be a simple "cmp original, CRC" or it can be done a little harder...
To find the place you could break on API's like CreateFileA, ReadFile... that kind of things, or use for example "bpm 00401000 rw"

Cya...

CoDe_InSiDe