Dunno if this has already been reported or not, but I've just installed Media Center 9.1.313 (over 9.1.309) and it freezes from time to time. My whole system grinds down to a snail's pace. The only thing to do is to kill the MediaCenter process in the task manager and start it again, but even bringing up the task manager and navigating to the MediaCenter process takes a minute or so because the system response is so godawful.
I don't know if this means anything, but it was playing an OGG file when it froze. It had just reached the end. I only have a few OGGs in my library, so it may be significant ... or not.
System Info
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Media Center Registered 9.1.313 -- C:\Program Files\J River\Media Center\
Microsoft Windows XP Workstation 5.1 Service Pack 1 (Build 2600)
Intel Unknown 1398 MHz MMX / Memory: Total - 523 MB, Free - 172 MB
Internet Explorer: 6.0.2800.1106 / ComCtl32.dll: 5.82 (xpsp1.020828-1920) / Shlwapi.dll: 6.00.2800.1276 / Shell32.dll: 6.00.2800.1233 (xpsp2.030604-1804) / wnaspi32.dll: N/A
Ripping / Drive D: Copy mode:Normal CD Type:Auto Read speed:Max
Digital playback: Yes / Use YADB: Yes / Get cover art: Yes / Calc replay gain: No / Copy volume: 32767
Eject after ripping: No / Play sound after ripping: No
Burning / Drive D: MATSHITA UJDA740 DVD/CDRW Addr: 1:0:0 Speed:8 MaxSpeed:8 BurnProof:Yes
Test mode: No / Eject after writing: Yes / Direct decoding: Yes / Write CD-Text: Yes
Use playback settings: Yes / Normalization: None