|To me it sounds like RAM. But you must have some RAM or the computer will not boot. The Computer does not require a Video Card to boot -- you just won't see anything. But it does require a keyboard and a properly hooked up Floppy if connected. (The most & greatest improper connection failure) The computer will halt with any wrong connection, such as a bent power pin, or a cable that is installed backwards.|
First I would remove RAM and clean the contacts with a pencil eraser to polish the contacts. Then use something like Tech Spray Isopropyl Alcohol (99% pure leaving no oily residue). If you are using more than one slab of RAM try only one slab. I also would run "Memtest86" (free) on each slab to detect memory errors. Memtest86 runs on a simple basic bootup floppy.
Now you can also test if it is your video card by simply using a basic floppy disc which boots into a DOS prompt. (Listen to the definite clicks on a friends PC when you use a floppy, its easy and simple knowing when you reached the prompt and which point you can shut down the PC and know whether your computer can boot to the point of loading an OS. )
If you can boot to the prompt it is your video card. I would also clean the Video card contacts, as discussed above. Make sure everything is properly seated, and all connected both power and data cables are properly seated.
Also you don't need a hard-drive to test the boot process. You can disconnect everything but a stick of memory, a floppy drive, and a keyboard, then replace device after device until you reach the device causing the problem using just a basic floppy disc after each added device. By using the floppy, it not only saves time to do each process, but also excludes any software and/or driver issues.