There are no additional plugins installed. And I misspoke, it's not the xppro native screen blanker, but rather the native "Turn off monitor" under Power Schemes that is conflicted. Right when the monitor should turn off it does so for a fraction of a second then comes right back on (and the cycle repeats until reboot). It definitely only happens after MC9 has been started (and even after exiting it).
Media Center Registered 9.1.226 -- C:\Program Files\J River\Media Center\
Microsoft Windows XP 5.1 Service Pack 1 (Build 2600)
Intel Pentium 4 1993 MHz MMX / Memory: Total - 261 MB, Free - 44 MB
Internet Explorer: 6.0.2800.1106 / ComCtl32.dll: 5.82 (xpsp1.020828-1920) / Shlwapi.dll: 6.00.2800.1106 (xpsp1.020828-1920) / Shell32.dll: 6.00.2800.1233 (xpsp2.030604-1804) / wnaspi32.dll: Internal ASPI Layer
Ripping / Drive R: Copy mode:ModeBurstBigBuffer CD Type:Auto Read speed:Max
Drive W: Copy mode:ModeBurstBigBuffer CD Type:IDE Read speed:Max
Digital playback: Yes / Use YADB: Yes / Get cover art: Yes / Calc replay gain: Yes / Copy volume: 32767
Eject after ripping: Yes / Play sound after ripping: Yes Soundfile: chord.wav
Burning / Drive W: YAMAHA CRW2200E Addr: 1:0:0 Speed:4 MaxSpeed:20 BurnProof:Yes
Test mode: No / Eject after writing: Yes / Direct decoding: No / Write CD-Text: Yes
Use playback settings: Yes / Normalization: None