CPU and hard disk type and speed is the most important, but if you write all the PC specs it will be better to understand which could be the best capture card for your hardware.

Agree with CapableMetal: if you can find out a S-VHS recorder is even better! JVC and Panasonic are the best brand for VHS/S-VHS decks; the best are the professional ones, that you could obtain now for a fraction of their cost as new, but be aware that probably the latter could have the head very (ab)used and so give a worst result than a low usage consumer model.