1.) what means "crashes" or how do you determine a crash? Can you access your router, ping, webif, telnet/putty, LAN/LAN aso.
2.) Which firmware is installed?
3.) Is your hdd connected with an own power supply? Type of HDD?
4.) Which Linksys do you mean? Usually a Linksys is a bit different, just a few have usb ports. USB Ports are one of the big advantages of an asus, most of the regular routers out there can not beat an asus.
newbiefan