Dell OptiPlex 755 - Dell doesn't recognise my Service Tag?

The only support for anything this old is limited to downloads and documentation -- see below.  

https://www.dell.com/support/home/en-us/product-support/product/optiplex-755/docs

I have seen occasionally genuine old Dell desktop s.t. is not recognized on Dell website. That is a normal though disappointing phenomenon.

You actually do not need Dell service tag to find drivers for your 755 MT.  This model is released prior to Win 10.  The only drivers available for download are for XP and Vsita.  If you are running Win 10, Microsoft automatically downloads all appropriate drivers for this pc and you do not need to install any driver manually.  I had installed Win 10 on 755 multiple units without any issue running all the hardware such as video, audio, Ethernet, dvd drive, hdd etc.

@redxps630​ I have Windows XP currently on my OptiPlex 755 MT. I just would like to find out if my PC will support an AMD or ATI Discrete Graphics Card and also would just like to get a personalised list of drivers + software for my particular unit.

Thank you for letting me know @ejn63​ and providing the link to downloads and documentation.

I have found out if you have a newer Dell gpu for Optiplex 7010/790 etc., as long as it has Dell driver for XP, you can still install on older Dell such as 755

Official 755 Dell
XP video drivers:

https://www.dell.com/support/home/en-us/product-support/product/optiplex-755/drivers

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=h2v4y&oscode=ww1&productcode=optiplex-755

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=jpxty&oscode=ww1&productcode=optiplex-755

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=vvvmh&oscode=ww1&productcode=optiplex-755

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=dh9d2&oscode=ww1&productcode=optiplex-755

@redxps630​ Thank you for providing me with a list of supported GPUs for my OptiPlex 755 MT Desktop. Any chance these GPUs will support Vista as well?

There are different drivers for vista 32 vs vista 64.  What is the DP/N of the gpu currently in your 755.  Which vista are you installing?

assuming vista 64

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=r197446&oscode=wv64&productcode=optiplex-755

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=r6xtk&oscode=wv64&productcode=optiplex-755

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=7crd1&oscode=wv64&productcode=optiplex-755

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=cpk61&oscode=wv64&productcode=optiplex-755

@redxps630​ I don't have a discrete GPU in my OptiPlex 755 MT yet. I'm still using Intel's GMA Graphics. I just wanted to know what my Discrete GPU Options are that will work on XP and Vista? But thank you for the links to Vista Graphics Drivers and yes I would like to try and install Vista 64-bit but I'm yet to buy an installation disc before I do anything.

Vista 64 disc image should be available for download in public domain or you can buy genuine Dell installation disc on eBay

I would install the latest Dell gpu c/w XP or Vista for 7010 or 790 which are backward c/w 755.  The original ATI and HD2400 are too old (starting from Opti 7020 Dell stopped supporting XP or Vista driver)

for example

vista 64 HD6450

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=hmnxk&oscode=wv64&productcode=optiplex-790

XP HD7470

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=38ymt&oscode=ww1&productcode=optiplex-7010

@redxps630​ Excellent, thank you very much for your help. Are the Dell Installation Discs tied to a specific system and have the product key on the contents of that disc or can it be used for any Dell System?

any Dell pc.  I have a bunch of these dvd someone gave to me during downsize.  I used them to install on my old Dell E310/510 without issue

PS

when I used a Dell XP dvd on a non-Dell old pc, it asked to activate within 30 days though.  I used the telephone method which worked.

@redxps630​ Well that's good to know. Thank you for your help on this forum. But speaking of the original question I asked. Why doesn't Dell recognise my OptiPlex 755 MT's Service Tag but it recognises my other Dell PCs? Is it due to age?