My wife recently bought me an Acer Extensa 5620 for Christmas. It's a great little unit with a lot of potential, but the one big flaw was the operating system: it came with Windows Vista. The fast hardware was crippled by the bloated, clumsy OS. I was therefore forced to figure out exactly how to get XP on it, so wrote up a guide to help others. It should apply to different Acer notebooks, and likely has info useful to other brands as well.
It's not as simple at it used to be. Today's laptops are 'meant' for Vista, so trying to install XP often isn't easy. In the case of my 5620, the hard drive wasn't even detected until I researched and changed Bios settings (known as the AHCI issue). I'm SO much happier after ditching Vista, though- when I first got it, a 1GHz Pentium III with XP could have run circles around it!
Step 1: Preparation
Don't immediately wipe Vista! It's actually useful for another hour or so. Use Acer's backup software (mine had an Acer floating toolbar with this) to do two things-
First, a Full Backup of your system. Trust me, if you ever have to send your Acer in for servicing, it better have Vista on it or your warranty could be voided. Plus, someday when you sell it, uninformed people think it's a plus point ;)
Secondly, why bother downloading random drivers you hope are the right ones? Acer makes it easy with its Driver and Application backup CD creator. A little known fact is that these drivers appear to be both the complete Vista AND XP set. Once you're done, you'll have burned three DVD's, and be ready for some XP goodness! If you've already wiped it, or just want the latest available, grab them from [ftp://ftp.support.acer-euro.com/notebook/ here]. I did both, just in case, throwing the newest onto a 256MB USB drive. Thirdly, look in Device Manager to see what AHCI Disk Controller you have! Write this down. On the Best Buy Acer Extensa 5620-6830, it's the 'Intel 82801HEM/HBM SATA AHCI.' Other models may be slightly different. This info is important later, and it can be difficult to find out without some annoying trial and error.
Step 2: Make the Bios Compatible
Reboot. Hit F2 to access the BIOS, and change the setting on the second page from AHCI to IDE (If you don't have this option, boot back into Vista and update your Bios, downloaded from the link above). On the Boot tab, change it so your DVD drive is first. Save changes and exit. Don't worry, we'll switch it back, but it's MUCH more of a PITA to leave it on when we install XP... unless you have a USB floppy drive sitting around, or like building slipstreamed XP disk ISO's!
Step 3: XP Installation
Pop in your XP CD and install like normal. My Acer had three partitions (10MB, 90GB, and 90GB); I killed them all and created a single one. The Recovery CD's we made -should- put everything back as it was, if we ever need it. After formatting my 200GB drive it's 186GB. Being on really new hardware it won't autodetect everything, but Don't Panic. We have all the drivers we need, thanks to our forethought in making that disc / thumb drive / whatever.
Step 4: Driver Setup
Once we're at the desktop, change your resolution to 800x600, then start installing drivers (some setup program buttons are cut off in the default 640x480). You probably want to start with the chipset driver, then the video drivers, sound, etc. On the Extensa 5620, even after installing the drivers you will likely have no sound at first and end up with a 'PCI Device' that is unknown; just right-click it and choose Update Driver. Let it automatically find it (it's the HD audio), and your sound should work after the next reboot. I rebooted every time it wanted to, then installed the next driver. This way they don't clash or get misconfigured. The webcam driver (both original and latest on the FTP) appears to install and work fine, but makes your system permanently hang when shutting down. Until we get a better driver, I just disable it to avoid having to hard crash every time. In theory, you can just enable it whenever you need to use it.
Step 5: Fixing AHCI
Everything working OK now? No exclamation marks or unknown hardware? Great! Now let's conquer the AHCI issue. On the driver CD, browse (don't auto-run) to the Drivers\ directory. Copy the AHCI folder to your C: drive, so now it's c:\AHCI\. Open the command line (Start -> Run -> cmd), and enter "c:\AHCI\setup.exe -a -pc:\" (without the quotes). This will pop up the setup utility. Click through it- it's not actually installing, but extracting the drivers for us to use. You'll find them afterwards in C:\Driver.
Now we manually install the driver into XP: Go to Device Manager, under IDE ATA/ATAPI controllers you should see something like: ICH8M SATA Controller. Right-Click on that and select Update Driver. Choose No to connecting to Windows Update to search, then hit Next. Select Install from a list or specific location (Advanced), hit Next, then select "Don't search. I will choose the driver to install." Hit Next again, then select Have Disk. Browse to your Drivers folder (C:\Driver), highlight the iastor.inf file, and hit Open. Select OK, then choose your AHCI driver (what we wrote down earlier, remember?). You'll likely have to uncheck the 'show compatible hardware' option to see the AHCI options. Again, on the Extensa 5620-6830, it's the Intel 82801HEM/HBM SATA AHCI Storage Controller- YMMV (Your Motherboard May Vary). Click next, ignore the warning that installing the device driver is not recommended, click Yes, Finish, then Yes to restart your computer.
Step 6: Finishing & Troubleshooting / Tips
When your computer reboots, hit F2 again to enter the BIOS. I changed my boot order back to HD first (shaves a whole 2-3 seconds off bootup time), but that's up to you. Change from IDE mode back to AHCI, save changes and exit. Once you boot to Windows, your computer will find and finish installing the "new" hardware, then likely ask to restart again.... but hooray! No more Vista!
Troubleshooting: If you still get a blue screen upon booting up, you may not have selected the correct AHCI driver. Reverting the Bios setting to IDE should get you back into XP to try again. If not, use F8 to go into Safe Mode and reinstall the controller driver there.
Tips: I ran into an issue where my favorite OpenGL screensavers won't run over 1fps on the 5620. After finding out that this is why (Intel disables OGL hardware acceleration on screensavers), I then found a workaround: rename screensavers to *.sCr instead of all lowercase. You may have to reboot, but then they should all work smooth again. This affects all X3100 users, or anyone with Intel GPU's.
Step 7: You're Done!
Congratulations, you now have a decent operating system on your spiffy new hardware! And it runs so much better. Remember, if you don't actually have Bluetooth on your laptop (Acer puts in a switch, but sells it lacking the module) then DON'T install the driver! It can cause issues.
The screenshot below is my Acer's desktop now. The next Instructable I post will explain how I got it to look like Vista, and some other tweaks you can do to speed up this or any other computer. Hope you found this helpful :)