One important thing you need to know when you are about to install a new internal hard drive in E521.
DO NOT TURN On THE COMPUTER IF YOU HAVE WRONGLY CONNECTED THE DATA CABLE.
I will explain about this now.
Before you install the new internal hard drive, or replacing the current hard drive to a bigger capacity, you should really mark or remember which Data Cable connects to which hard drive.
If you connect the data cable wrongly to the hard drive that doesn't belong to it, and if you turn on your computer, you will not be able to boot properly. This only applies to Windows unfortunately.
This is what i have done and I am telling you that you mustn't do the same.
1. My E521 shipped with 250Gb of internal hard drive. No second hard drive.
2. I wanted to install the second hard drive so i bought 500Gb of internal hard drive.
3. I unplugged the powercable and the data cable from 250Gb hard drive because i wanted the 500Gb hard drive to be in the first slot. I also wanted to clean the dust.
4. 500Gb of empty hard drive in the first slot and current 250Gb hard drive in the second slot.
5. I plugged in the power cable and the data cable for both of them. I have forgotten which data cable belongs to which. Certainly, the data cable for 250Gb should have connected to 250Gb! But I didn't.
6. I turned on the PC and now I can't boot. Seems like some data necessary to boot is missing.
There was nothing I could do. Repair disk won't help at all. I reinstalled the XP.
So this is what i have done so many times. It is best not to unplug the data cable of your current hard drive unless you know THAT data cable belongs to your current hard drive.. I really suggest you to mark the number on the tag.
The symtop only appears if you wrongly connected your data cable to the Main Hard drive where you store your primary OS.
Please note that once you got into the situation where you can't boot the windows because of the mistake I mentioned, You can not boot the OS properly again even you reconnect your data cable to the right ones.
Another problem will rise when you replace your current Sata device.
There are four SATA cable slots on the motherboard in E521. Two of them belongs to the DVD/CD Drive and the other two belongs to the hard drive. All of them are SATA.
If you have two DVD drive and two internal hard drive already, and if you want to replace one of them to the new ones, MAKE SURE YOU KNOW WHICH DATA CABLE BELONGS TO WHICH.
When you want to replace the device, just unplug the data cable (and the powercable) of that device only and replace with the new one. DO not unplug everything for replacing one device.
DO not replace all at once if you are planning to replace all of them. Do it one by one.
The most important cable is the hard drive data cable.
If you have any questions, please don't hesitate to email me. Thank you.