Windows 95 locking Up every month

We have been running 16 bits Telephony-office-Linx (Unified Messaging Solutions-Voice mail)on windows 95 plateform. System will lockup without any reason; however, we made sure and isolated the problem with our voice mail (Telephony-office-Linx)software, confirmed that Application software is not the root cause. Any idea…all INputs would be highly appreciated..