The Conroe865GV (no to confuse with the godly Conroe865PE) has an AGI slot... which basically is a PCI slot with AGP form factor. I wouldn't put anything above a Radeon 9200 in there, won't do much good in games. VGA support list: http://www.asrock.com/mb/Intel/ConRoe865GV/?cat=VGA
You'd be better off with a PCI card. Maybe a GT520 PCI? http://www.zotacusa.com/geforce-gt-5...50610-10l.html
Has HDMI out.
The freezing issues might have to do with RAM latencies. I don't know what sorcery Asrock used on these boards but Core 2 CPUs require CL2.5 RAM for some reason (might have to do with NB timings, PAT perhaps? dunno) . If your RAM isn't CL2.5 you can run it in Flexible Mode and will force them into 3:2 CL2.5.