Can CP nevertheless recover the reasonable value of its service?
Yes, because HDS was continuing to use programs created by CP for which, as HDS knew, CP expected to be paid. 
No, because failure of an express condition precedent excused HDS from any duty to compensate CP. 
No, because such a recovery by CP would be inconsistent with a claim by HDS against CP for breach of contract
Yes, because continued use of the programs by HDS would save at least $12,000 a year. 