I need to change my comp & will be doing so in a 2 months or so. Meanwhile I need to have higher capacity hard disk & I am thinking of getting 250/300 GB sata fitted in external case with external power supply. My present system runs XP pro P4/1.7 intel 845 glad MB, 512 mb Ram. Will sata hard disk work as normal with my present system using old Samsung disk. I will connect using it via usb port. I remember there is a convertor cord to bridge the different type of hard disk, I also know that the sata disk will not run at its peak speed if used with old hard disk. My plan is to buy Dual layer DVD writer which can work with present system & I can use these 2 items when I buy new comp. What problems can I run into, I tried once adding 200gb normal hard disk to this system & it gave me only 130 GB of that disk, seems some limit of the mother board I have, so will it treat 250 sata the same way (not much of a issue since I will upgrade soon) What else can I face problems if any.