How to Activate Vista

Assuming you bought a Dell Windows Vista Reinstallation DVD from eBay. These are only designed to work for systems which already have a Windows Vista license. The Dimension E510 has a COA for Windows XP Home Premium thus has no license for Windows Vista therefore it is not legal to use.

System Locked Preinstallation will likely not work on your system. Windows Vista will install but not activate as you have observed. However it might if the system has the latest BIOS revision. Dell might have sold later versions of this model with Windows Vista:

http://ftp.dell.com/bios/D5150A07.EXE

Although it might work it is not legal to activate on this system without an accompanying COA or license. 

You should not buy a Dell Windows Vista Reinstallation DVD in this case but an "Upgrade Windows Vista DVD".

However there is no point in buying Windows Vista when Windows 7 and 8.1 are far superior and will also work on your model. Upgrade licenses come with a unique 25 digit product key which are used for product activation.

If you want to try a keyless install of Windows 7 (for a 30 day trial) download a Windows 7 Home Premium 64 bit .iso from here:

http://philipyip.wordpress.com/download-microsoft-windows/windows-7-sp1-iso-download/

Follow Windows Reinstallation Guide/A Clean install of Windows 7:

http://philipyip.wordpress.com/dell-community-forums/

Again system Locked Preinstallation won't work for you so ignore Step 2.

Then use the following drivers here:

http://philipyip.wordpress.com/unofficial-driver-sets/dimension-desktops/dimension-5150-windows-7-64-bit/

You may then buy a Windows 7 Home Premium upgrade license and use this for product activation.

For Windows 8.1 there is no means of downloading a retail .iso for evaluation purposes. You can however download the Enterprize evaluation and clean install with it:

http://technet.microsoft.com/en-us/evalcenter/hh699156.aspx

Windows 8.1 will contain most of the drivers necessary for this system. You will need to however clean install with retail media after you purchase a license.

Note it is often cheaper to buy a Windows 8 Upgrade for example: http://www.amazon.co.uk/Windows-Pro-Upgrade-Edition-Vista/dp/B008GRKGXK opposed to Windows 8.1 directly: http://www.amazon.co.uk/gp/product/B00FRAE7MU/ref=pd_lpo_k2_dp_sr_2?pf_rd_p=103612307&pf_rd_s=lpo-top-stripe&pf_rd_t=201&pf_rd_i=B008GRKGXK&pf_rd_m=A3P5ROKL5A1OLE&pf_rd_r=0644QNN4YND5K951N789

You can then use the following workaround with the Windows 8 product key here:

http://philipyip.wordpress.com/download-microsoft-windows/download-windows-8-1-iso/

To obtain Windows 8.1 installation media for clean install. See Windows Reinstallation Guide/A Clean Install of Windows 8.1 for more details.

Windows 8 Pro upgrade is $90 at Newegg

Thank you for the information. This computer came out in 2006 with the XP OS and later came with Vista. I know the MOBO supports Vista. I don't know if the MOBO is compatible with Windows 7 and 8. Two years ago I tried to upgrade a HP computer from Windows Vista to 7 and had nothing but problems. I found out on a forum that the MOBO did not support Windows 7, so I had to buy a new MOBO to use Windows 7.

 I was unable to find information on the Dell website on how to upgrade the OS to Vista. How can I buy an "Upgrade Windows Vista DVD" from Dell?

Firstly anything that can run Windows Vista can run Windows 7. I don't know what happened with your HP.

Secondly I have provided you Windows 7 drivers for your system.

Thirdly I have shown you how to install Windows 7 as a 30 day trial via a clean install. I advise you to install this and see how the system performs before parting with any money.

In addition if you still have the Windows 7 upgrade license and media from your HP, you can simply remove it from the HP and transfer the upgrade license to the Dell providing you bought a correct upgrade disc.

You will be hard pushed to buy a Vista upgrade from Dell as Vista is not really being sold now. Dell seem to only be selling the Windows 8.1 upgrade:

http://accessories.us.dell.com/sna/productdetail.aspx?c=us&l=en&cs=19&sku=A7217980&baynote_bnrank=0&baynote_irrank=2&~ck=dellSearch

As mentioned the same product is sold for cheaper elsewhere.

I wanted to see if the computer was compatible with windows 8. I put a spare hard drive in the computer and then put the Windows 8 disk in and the computer installed Windows 8 witn no problems. It appears to work fine. My concerns about this old computer  being windows 8 capable were unfounded.  Thanks for your help.

Great, did you install 32 Bit or 64 Bit? 

Also did you manage to update to Windows 8.1?

There have been some issues with the 64 Bit version of 8.1 on these models due to elevated system requirements for the 64 Bit version. In these cases the 32 bit version works fine.

I would Check out the Microsoft FAQ's help topics, and call a rep.

Sorry to be so late responding. I had installed Windows 8, 32 bit on the computer so I decieded to see if the 64 bit version would install. I reconnected the spare HD and it loaded the Windows 8 32 bit OS with no problem. I put the 64 bit version in the DVD drive and got an error msg that I could not upgrade but would have to boot off the DVD to install Windows 8, 64 bit. I couldn't get the computer to boot off the DVD. I found that the computer doesn't really turn off but Windows 8 is still running and you don't go thru the usual POST sequence of checking all the drives. I had to unplug the computer to really turn it off and get it to boot from the DVD. That's another reason to dislike Windows 8. The computer then successfully installed windows 8, 64 bit. Windows 8 works ok in both versions.