If you're one of those guy who bought themselves this laptop with Windows Vista preinstalled, yet still want to use WinXP, you can read the following guide in the link below. It didn't require you to delete your original OS, instead, the guide teach you how to dual-boot both Vista and XP.
The guide is pretty much self-explained and it includes most of the link to download the drivers for WinXP as you can't find much about those drivers for WinXP in ACER official website.
* There's something missing in that guide though, which is the part where you need to change the hard disc mode from Advanced Host Controller Interface (AHCI) to IDE mode. If you didn't change it, upon booting your laptop with XP bootdisc it won't be able to locate any suitable drives to install XP as XP cannot detect SATA drive. After installation you also need to change the windows bootloader file as XP will overwrite the bootloader file for Vista. In other words, after installing XP you won't be able to boot into Vista unless you modify the bootloader file. To do so, you can download VistaBootloaderPro.
1. Download VistaBootLoaderPro.
2. Boot into XP and install it.
3. Modify the option to allow the bootloader to be overwritten as Vista bootloader file.
4. Restart your computer.
5. Boot into Vista.
6. Install VistaBootLoaderPro again.
7. Do step 3 and allow the bootloader to overwrite the Legacy (XP) file.
8. Restart and you can now dual-boot your OS.
Since the data/file transfer rate in IDE mode is rather slow than SATA, I highly advise you to go to the BIOS again and change the hard disc mode to AHCI. However, doing so will result in the blue screen of death (BSoD) when trying to boot into XP. So before changing the mode, boot into XP, find the related hard disc drive (which is Intel ...) SATA driver and install it. Only then you are safe to change the hard disc mode.