You say it trembled and blacked out 10 min or so after install of debian linux. Debian Linux is a Operating System and as I recall on the box of most video cards it specifies what operating system it works on, mostly the Windows Operating system like WinXP, Win9x, WinME.

Otherwise, your assumption about the power suppy seem viable. If you have added anything since buying the Dell computer, that plus the video card could be putting a strain on the Power supply. Replacement power supply in the range of 400-500W can be purchased at a reasonable cost and easily installed. Dell, however is a little different and you must check to get one specifically for Dell.