HTPC Problem

I finished my HTPC build about a month ago and I'm having a problem with my IR receiver (HP p/n 5187-4583). Everything worked fine until a week ago and I was unable to wake the HTPC from sleep mode (S3) using the remote. Could still wake machine by pressing case's power button or using the wired keyboard. The remote still functioned correctly when navigating thru XBMC.Does anyone have any insight? I don't like having to get up from my recliner to wake my HTPC.

Asrock E350M1 mobo in a MI-008 case
70GB SSD
HP 5187-4583 IR Receiver with HP WMC Remote
Windows 7 Pro 64-bit