Just download regdrop (
http://www.addisonsw.com/text/regdrop.zip) and drop dvobsub.ax (windows\system) onto it with holding shift (same as using "regsvr32 /u pathx\dvobsub.ax"); the filter is now unregistered. Just drop it onto regdrop without holding shift to register it again (same as using "regsvr32 pathx\dvsub.ax"). Imo dvsub doesn´t take that much resources but as it´s nescessary only rarely with bsplayer this seems to be a convenient way to get rid of it temporarily. Just make sure that vobsub.dll and unrar.dll are copied to windows/system dir and you can even install dvsub completely manual.