I've been trying to post, but failing so apologies if I get multiple posts!
If FB's suggestion doesn't work, download and run the free Slimdrivers. It will come up with numerous missing/ out of date drivers. Only download those you are actually missing (they will usually be from the manufacture's site. E.G. I've just reinstalled XP and VGA and sound were missing. Slimdrivers pointed me to Nvidia and realtek).
Lotvic's is the way forward. If you can identify your motherboard - something like Belarc Advisor can help - then you just need to find, download and install the drivers for your motherboard from the manufacturer's web site.
Hmmm - don't give up. The motherboard might have been built for Acer (almost certainly was) by a motherboard manufacturer. Their generic drivers may well work. I'm sure I'm stating the bleeding obvious - but have you Googled 'Acer your PC model] XP drivers'? There's a lot of stuff out there that may well work, even if it's not hosted by Acer. And failing that, given that you've got nothing to lose, you could try using drivers for Acer machines other than yours, on the basis that there is typically a lot of commonality between hardware platforms. Like from here, for example.
I've been on so many missions in my life to track down missing drivers... :-(