Is your compaq loaded with win98 or XP? Aside from some of these 50 dollar drugstore cameras, most digital cameras are engineered to be compatible with USB drivers built into the XP, Vista, Seven libraries.
If it's Win98, here's a link to the driver. The link will reiterate what I said about drivers for XP. None needed.
http://esupport.sony.com/US/perl/swu-list.pl?mdl=DSCP52
If it's XP, well that is an old camera and maybe the USB interface got zapped by a previous owner. A memory stick reader can be found for around $10-15 in the USA at computer stores.
If it's WIn98 and still don't work, then you have to go the card reader route too. It might be hard to find a card reader that still comes with win98 drivers.