Although Qezxplayer plays some flvs but its not upto the mark...Ok so this method requires encoding flv to avi but its way too fast than using any video converter..Just open your .flv files in Virtualdub and under the video and audio menus choose direct stream copy.Now save the file as avi.There you go watch it on zmplayer or others which support avi..

Note:1.You require FLV Input Plugin for vdub to open flv which can be found here Moitah.net.. unzip FLVInputDriver.vdplugin to your VirtualDub\plugins folder

2 .Also .NET Framework 2.0 is required..look at the site for details.

Flvs can be downloaded from youtube or tudou.com as their resolution is already 320x240