I got here a 160GB samsung HD161GJ hard disk which can be detected in bios and also found as ''working properly'' in device manager. However, the problem is the drive is not visible in windows explorer. I also cannot see it in disk management in administrative tools. What seems to be the problem? Can you help me solve this? pleeease!!

I think it is either an issue with the hard disk or with the operation system ..If the operation system is damaged you will need to reinstall it ..This can be done from recovery partition or disk ..and in case you don't have such tools..use a boot-able disk with the operation system ..
There might be a different cause for this..if you changed teh settings for the bios..In this case usually it should give you a blue screen ..but who knows maybe will work ..
The fact that it says it do not found the operation system it makes me think it does not detect the hard drive ..and in this case go to bios by pressing F2 on start ..and in this window ..look on the first tab ..and locate the devices (hard disk ) ..and if it has the AHCI function on ..select it and disable it and let it run ide compatible ..Press F10 to save the settings made..and restart ..If this was the issue ..it will load the system right the way .This may be caused by a damaged ahci driver ..or if it never worked on that and you went to bios and restored it to default and automatically enabled the ahci function and it had no driver for it in the system ..
Good luck ..and let me know what you've managed to do ..

Hello,Please check the BIOS to see if the SATA ports are enabled. Older boards will disable the sata ports in the BIOS by default. To enter the BIOS, hit the DEl key as soon as you boot the PC.
If ports are enabled, then you probably have to format the drive.Heres how:1. Right-click My Computer and select Manage.
2. Under Storage, click Disk Management on the left pane.
STEP 3 - Format the device / drive / MP3 player
1. Right-click on the 1 TB drive you want to format then select Format.Windows will not recognize the drives file system and will mount it with a drive letter. ex; E:

As long as you are sure the hard drive is connected properly with SATA cables to the motherboard and has power from the power supply unit, and that the drive is working, you can enter the BIOS on computer startup and modify the "boot device" look in "primary boot device" for a name matching that of your hard drive (probably "HITACHI .....) If it is there select it as the primary device and hopefully it will boot and ask you to install windows. If it is not there the drive may not be connected or it may need to be replaced. Hope this helps!

You need to ensure if the hard disk is compatible with the motherboard.

OK ...this is happening cause of a feature called ahci enabled in bios for the sata HDD ..this have to be disabled in order to be able to find the hard disk without the AHCI driver installed like a 3rd party (To do that just go to bios by pressing F2 on start immediately after first screen lights up ...and in Bios ..go to advanced..or devices..it sthe second or the 3rd option ...and in there look for the sector where th rdrives are detected..the HDD and teh cd drive ..in there you will find when you choose the HDD the AHCI function ..and you have to disable it ...than press F10 to save the changes..and it will work ..
the drivers you need are available on the support site ..
http://www.csd.toshiba.com/cgi-bin/tais/support/jsp/modelContent.jsp?ct=DL&os=&category=&moid=1998596&rpn=PSAE3U&modelFilter=A205-S5855&selCategory=2756709&selFamily=1073768663

The Aspire 1641 is supplied with a 80Gb hard drive. If the new 160Gb hard drive is not detected in the BIOS then the BIOS cannot support this size hard drive.
Check your manual/specification to see the maximum size hard drive it can support.
You can install the 160Gb hard drive in an USB hard drive adapter case and use it as an external USB hard drive.

Take It back and get a new one .

control panel
computer management
disk management
select the disk and iniatlize by right clicking.

flash bios

it seems that your computer might have a SATA hard drive which could not be detectable by windows xp, try to install vista it will detect it easily.

otherwise use dm (disk manager) for detection and partition.